Bullet 2.63 RC1 released: faster pair manager, gimpact 0.3

[Erwin Coumans]

Here is a first release candidate, Bullet 2.63-RC1.

- Added fast hashtable-based pair manager to store broadphase collision results. Thanks to Pierre Terdiman for the suggestion, and Erin Catto for some implementation details in his Box2D library.
- Francisco Leon provided the new GIMPACT 0.3 concave mesh collision library.
- BulletColladaConverter is now a separate library in Extras, instead of embedded in the ColladaDemo. Thanks to Srekel for suggestion.
- fix for crash in optional Extras/box-box, related to new pool memory
- Extras/quickstep improvements, thanks to Remotion
- General performance improvements and minor fixes.

Download Bullet-2.63-RC1 here.

Any feedback is welcome!
Enjoy!
Erwin