Keep a reference to Tuning and Raycaster in vehicles

... so garbage collector will not collect/dispose them while being used
Merge pull request #3 from VirusFree/pull_request

Keep a reference to Tuning and Raycaster in vehicles
Rewrite all vehicle classes as managed.
Rename IActionInterface to IAction.
Add Generic6DofSpring2Constraint.
Fix math functions.
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
allow null CollisionShape and MotionState
Fix invalid native manifold delete bug

active unmanaged manifolds were being deleted at garbage collection.
fix RaycastVehicle base fwd axis

fixes wheel rotation calculations