Add in offset for packed sprites

Many sprite animation (Adobe Edge) tools pack the sprites in such a way that the
size of the image is optimized.  In order to play the sprite properly
you need to change the x and y coordinate of the image so the sprite
plays properly.  Here is an example where the bunny's feet are supposed to stay still and the body are supposed to move. Instead of ducking because of the way it is packed he looks like he is jumping.

![lb_robot](https://cloud.githubusercontent.com/assets/4871423/4984121/cf22be80-6920-11e4-82ff-6816c3acb9d8.png)

Currently in Kineticjs there is no place to store this
offset data.  I added the offset data optionally to the sprite object
and changed the scene function to use it if it exists.

here is the code that fits with that sprite
 newTarget.KI = new Kinetic.Sprite({
                                      image: tarImage,
                                      x: newTarget.left,
                                      y: newTarget.top,
                                      hitGraphEnabled: false,
                                  animation: 'robot',
                                  animations: {
                                      robot: [
                                              0,0,103,174,
                                              103,0,103,174,
                                              103,0,103,174,
                                              103,0,103,174,
                                              103,0,103,174,
                                              206,0,107,174,
                                              313,0,113,174,
                                              426,0,116,179,
                                              542,0,120,178,
                                              662,0,120,180,
                                              782,0,120,180,
                                              782,0,120,180,
                                              782,0,120,180,
                                              782,0,120,180,
                                              902,0,120,180,
                                              1022,0,121,181,
                                              1143,0,96,175,
                                              1239,0,97,174,
                                              1336,0,96,174,
                                              1336,0,96,174,
                                              1336,0,96,174,
                                              1336,0,96,174,
                                              1336,0,96,174,
                                              1432,0,96,174,
                                              1528,0,99,176,
                                              1627,0,126,164,
                                              1753,0,139,152,
                                              1892,0,143,159,
                                              0,181,145,159,
                                              145,181,143,159,
                                              288,181,141,159,
                                              429,181,139,159,
                                              568,181,140,159,
                                              708,181,140,159,
                                              848,181,140,159,
                                              848,181,140,159,
                                              848,181,140,159,
                                              848,181,140,159,
                                              848,181,140,159,
                                              848,181,140,159,
                                              988,181,140,159,
                                              1128,181,136,153,
                                              1264,181,141,170,
                                              1405,181,105,174,
                                              1510,181,103,174,
                                              1510,181,103,174,
                                              1510,181,103,174,
                                              1613,181,103,174,
                                              1716,181,104,175,
                                              1820,181,110,175,
                                              1930,181,116,178,
                                              0,359,119,181,
                                              119,359,119,180,
                                              238,359,119,181,
                                              238,359,119,181,
                                              238,359,119,181,
                                              357,359,119,181,
                                              476,359,122,181,
                                              598,359,98,176,
                                              696,359,95,176,
                                              791,359,95,175,
                                              791,359,95,175,
                                              791,359,95,175,
                                              791,359,95,175,
                                              791,359,95,175,
                                              886,359,95,175,
                                              981,359,99,175,
                                              1080,359,136,163,
                                              1216,359,134,156,
                                              1350,359,141,159,
                                              1491,359,144,159,
                                              1635,359,141,159,
                                              1776,359,138,159,
                                              0,540,136,159,
                                              136,540,137,159,
                                              273,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              412,540,139,159,
                                              551,540,141,170
                                              ]
                                  },
                                      offsets: {
                                      robot: [
                                              51,7,
                                              51,7,
                                              51,7,
                                              51,7,
                                              51,7,
                                              52,7,
                                              56,7,
                                              55,2,
                                              53,3,
                                              53,1,
                                              53,1,
                                              53,1,
                                              53,1,
                                              53,1,
                                              53,1,
                                              47,0,
                                              47,6,
                                              47,7,
                                              47,7,
                                              47,7,
                                              47,7,
                                              47,7,
                                              47,7,
                                              47,7,
                                              40,5,
                                              13,17,
                                              2,29,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              0,22,
                                              4,28,
                                              0,11,
                                              49,7,
                                              51,7,
                                              51,7,
                                              51,7,
                                              51,7,
                                              30,6,
                                              21,6,
                                              19,3,
                                              18,0,
                                              18,1,
                                              18,0,
                                              18,0,
                                              18,0,
                                              18,0,
                                              22,0,
                                              43,5,
                                              46,5,
                                              46,6,
                                              46,6,
                                              46,6,
                                              46,6,
                                              46,6,
                                              46,6,
                                              50,6,
                                              52,18,
                                              50,25,
                                              47,22,
                                              44,22,
                                              47,22,
                                              50,22,
                                              52,22,
                                              51,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              49,22,
                                              50,11
                                              ]
                                      },
                                  frameRate: 12,
                                  frameIndex: 0
                                  });