Merge pull request #7 from leomuona/master

Added Bullet Physics 2.81 engine sources
Parsing of COLLADA interpolation and IN/OUT tangents.
assert for vector sizes before parse.
Keyframes parsed.
Keyframes now in joints.
Working keyFrame animation from COLLADA.

Rendering hardcoded but works, Next should interpolate between
keyframes.
setupBindPoseMatrices function for Skeleton.
Linear interpolation between vectors.
lerp between keyframes.
Working lerp and keyframe animation!

Still something wrong with last and first frame lerp,
Seems to just jerk there. Also fixed few bugs from prev commits.
Removed commented code...
Removed some redundant code/build files.
User controlled camera.

Also replaced gluLookAt with own modelview matrix calcs.
function to create unique box
COLLADA skeleton parse fix, reads blender exports.
Merge branch 'master' of github.com:jesseniemisto/skeletor
adding box and box converter, we will need this to create floor.
Creating the floor box. Next up is to render the box and create physics simulation call.