First stage in refactoring Bullet: moved Bullet Collision and Dynamics and LinearMath into src folder, and all files in Collision Detection and Dynamics have bt prefix.

Made all buildsystems to work again (jam, msvc, cmake)

src/BulletDynamics/Jamfile

@@ -0,0 +1,9 @@
+SubDir TOP src BulletDynamics ;
+
+Description bulletdynamics : "Bullet Rigidbody Dynamics" ;
+Library bulletdynamics : 
+  [ Wildcard ConstraintSolver : *.h *.cpp ] 
+  [ Wildcard Dynamics : *.h *.cpp ] 
+  [ Wildcard Vehicle : *.h *.cpp ] 
+;
+Recurse InstallHeader : .h  ;