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)

Extras/ConvexHull/CMakeLists.txt

@@ -0,0 +1,10 @@
+INCLUDE_DIRECTORIES(
+${BULLET_PHYSICS_SOURCE_DIR}/src ${BULLET_PHYSICS_SOURCE_DIR}/Extras/ConvexHull
+)
+	
+ADD_LIBRARY(LibConvexHull
+btConvexHull.h
+btConvexHull.cpp
+btShapeHull.cpp
+btShapeHull.h
+)