Fix float precision issues and mixed usage of Math.sin, MathUtils.sin

The mixed usage of both the high-precision and the faster trig functions
can leads to very different results and problems due to the nature of the
faster methods.

Also, the MathUtils implementation produces some slightly different results
when, for example, rotating a matrix on an arbitrary axis.
Merge pull request #303 from xoppa/bullet

Bullet, small changes
Merge pull request #302 from manuelbua/quat-fix-mixed-sincos

Fix float precision issues and mixed usage of Math.sin, MathUtils.sin
Add btManifoldPoint#getUserValue/setUserValue
Add GdxCollisionObjectBridge
Add GdxCollisionObjectBridge #2
Add ContactAddedListener, ContactProcessedListener and ContactDestroyedListener.
Swig generated files
Add ContactCallbackTest