fix some warnings, disable gimpact by default in world importer,

use DIRECTLY_UPDATE_VELOCITY_DURING_SOLVER_ITERATIONS by default for now,
until we find the issue with some failing test cases in btMultiBody
fix a crashing issue in MyMultiBodyCreator.cpp (uninitialized variable)
disable excessive debug printf in URDF2Bullet

examples/BasicDemo/BasicExample.cpp

@@ -73,7 +73,7 @@ void BasicExample::initPhysics()
 
 	{
 		btScalar mass(0.);
-		btRigidBody* body = createRigidBody(mass,groundTransform,groundShape, btVector4(0,0,1,1));
+		createRigidBody(mass,groundTransform,groundShape, btVector4(0,0,1,1));
 	}
 
 
@@ -113,7 +113,7 @@ void BasicExample::initPhysics()
 										btScalar(2.0*j)));
 
 			
-					btRigidBody* body = createRigidBody(mass,startTransform,colShape);
+					createRigidBody(mass,startTransform,colShape);
 					
 
 				}

examples/BasicDemo/main.cpp

@@ -24,7 +24,6 @@ subject to the following restrictions:
 
 int main(int argc, char* argv[])
 {
-	struct PhysicsInterface* pint = 0;
 	
 	DummyGUIHelper noGfx;