change updateData parameter type to void *
change updateData parameter type to void *
add method lockMemoryPartial, and change lockMemory return value type to void *
change updateData parameter type to void *
change lockMemory return value type to void *, call superclass method in releaseMemory
change updateData parameter type to void *, add fields loaded_width and loaded_height
change updataData parameter type to void *, call glTexSubImage on texture updates, remember loaded texture size so that glTexImage2d can be called if the size changes
add Texture.cpp, and place decRefcnt method in it
refactor
do not create texture id until it is needed