Various changes, mostly bullet related

Dont look at the changes, its huge, instead check the individual commits

- Re-enable shadows for the bullet tests, use BaseBulletTest.shadows to enable/disable them. We might want to disable them for ios.
- Update to swig 2.0.12, nothing changed thats relevant to the wrapper.
- Update to bullet project to visual studio 2013 (still use vs2010 emulation)
- Add CharacterTest to show how to use btKinematicCharacterController
- Changed GL10 to GL20 in the swig interface
- PathTest was removed in https://github.com/libgdx/libgdx/commit/38e65331c71f092470a2c193adcbf2a75f05251d, added it back and updated it to gles20.