Animation notif, lhplist ext, box2d transform

Added animation notifications
Fixed a box2d transformation issue
Now levels are published with "lhplist" extension - refactored demos
Updated documentation comments
New Joints, New Demos, Bug Fixes

Fixed issue with loading assets with joints
Fixed issue with loading traced physics shapes when object inside asset.
Added all joints
Added new demos for the some of the new joints.
Fixed issue with calling begin collision callback when dealing with sensor bodies.
Fixed a couple of animation issues.
Updated character animation demo.
Added Mac OS target
Merge pull request #5 from vladubogdan/develop

Bug fixes, New Joints, Notifications, Box2d Transformations, Mac OS Target