Sync with Bullet.
fix vs2013 solution path
fixes for double precision
add Move() for characters
Add IsEnabled for KinematicCharacter
Add Reset in RayResultCallback to allow reuse of object and avoid expensive reallocation/garbage.

Also added Set(ref from,ref to) for more efficient vector handling
fix matrix math
get shapes from contact point
report manifold contact count (as to avoid getting manifold in c# just to check contact count)
add scale setter for UniformScalingShape
add helper to compute compound shape connectivity
workaround for static actors shape
fix build error