free memory for btShapeHulls, keep track of it in GL_ShapeDrawer.

move btShapeHull and btConvexHull into its own library in Extras/ConvexHull (it allocates memory using mem/delete and refactoring into using btAlignedAlloc/Free takes too much time)
fix heightfield / btOptimizedBvh for quantization, so that raycast can use quantized aabb (clamp up for maxima and down for minima)

work-in-progress (update projectfiles etc)

Demos/GimpactTestDemo/GimpactTestDemo.cpp

@@ -152,7 +152,7 @@ void GimpactConcaveDemo::renderme()
 				}
 			}
 
-			GL_ShapeDrawer::drawOpenGL(m,colObj->getCollisionShape(),wireColor,getDebugMode());
+			m_shapeDrawer.drawOpenGL(m,colObj->getCollisionShape(),wireColor,getDebugMode());
 		}