Added drawing exceptions when target is not properly ready.
Now, Canvas::update() Canvas::draw() will return InsufficientCondition
if the target has not been set beforehand.
GlRenderTarget contains framebuffer and render target objects,
these GPU resources need to be released before reusing the structure and calling init with the new size.
Performing a full-screen RenderPass resolve is too expensive.
Because most composite cases only require a small area to be rendered off-screen.
To improve performance, use the bounds of the Geometry for off-screen rendering whenever possible
