More GJK degeneracy fixes, thanks Jacob Langford for the feedback:

http://code.google.com/p/bullet/issues/detail?id=250

Added missing files for Maya Dynamica plugin
Thanks Herbert Law for the patch, and damrit and others for the report
http://code.google.com/p/bullet/issues/detail?id=231

Fix btQuaternion shortestArcQuat, thanks Stan Melax for original fix and shogun for reminder
http://bulletphysics.com/Bullet/phpBB3/viewtopic.php?f=9&t=1989

Implemented btDiscreteDynamicsWorld::removeCollisionObject (and btSoftBodyDynamicsWorld) to avoid
crashes. Thanks Jacob Langford for bringing that up.

Minor sphere-debug drawing issue (spheres were drawn inside-out (wrong face winding)

src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.cpp

@@ -416,11 +416,19 @@ btVector3 btDiscreteDynamicsWorld::getGravity () const
 	return m_gravity;
 }
 
+void	btDiscreteDynamicsWorld::removeCollisionObject(btCollisionObject* collisionObject)
+{
+	btRigidBody* body = btRigidBody::upcast(collisionObject);
+	if (body)
+		removeRigidBody(body);
+	else
+		btCollisionWorld::removeCollisionObject(collisionObject);
+}
 
 void	btDiscreteDynamicsWorld::removeRigidBody(btRigidBody* body)
 {
 	m_nonStaticRigidBodies.remove(body);
-	removeCollisionObject(body);
+	btCollisionWorld::removeCollisionObject(body);
 }
 
 void	btDiscreteDynamicsWorld::addRigidBody(btRigidBody* body)

src/BulletDynamics/Dynamics/btDiscreteDynamicsWorld.h

@@ -130,6 +130,9 @@ public:
 
 	virtual void	removeRigidBody(btRigidBody* body);
 
+	///removeCollisionObject will first check if it is a rigid body, if so call removeRigidBody otherwise call btCollisionWorld::removeCollisionObject
+	virtual void	removeCollisionObject(btCollisionObject* collisionObject);
+
 	void	debugDrawObject(const btTransform& worldTransform, const btCollisionShape* shape, const btVector3& color);
 
 	void	debugDrawConstraint(btTypedConstraint* constraint);

src/BulletDynamics/Dynamics/btSimpleDynamicsWorld.cpp

@@ -132,9 +132,19 @@ btVector3 btSimpleDynamicsWorld::getGravity () const
 
 void	btSimpleDynamicsWorld::removeRigidBody(btRigidBody* body)
 {
-	removeCollisionObject(body);
+	btCollisionWorld::removeCollisionObject(body);
 }
 
+void	btSimpleDynamicsWorld::removeCollisionObject(btCollisionObject* collisionObject)
+{
+	btRigidBody* body = btRigidBody::upcast(collisionObject);
+	if (body)
+		removeRigidBody(body);
+	else
+		btCollisionWorld::removeCollisionObject(collisionObject);
+}
+
+
 void	btSimpleDynamicsWorld::addRigidBody(btRigidBody* body)
 {
 	body->setGravity(m_gravity);

src/BulletDynamics/Dynamics/btSimpleDynamicsWorld.h

@@ -57,6 +57,9 @@ public:
 	virtual void	addRigidBody(btRigidBody* body);
 
 	virtual void	removeRigidBody(btRigidBody* body);
+
+	///removeCollisionObject will first check if it is a rigid body, if so call removeRigidBody otherwise call btCollisionWorld::removeCollisionObject
+	virtual void	removeCollisionObject(btCollisionObject* collisionObject);
 	
 	virtual void	updateAabbs();