Refactor the GlCanvas::target() interface to allow
passing the drawing target ID from the user side.
Previously, it performed the drawing on the currently set FBO target.
Beta API change:
Result GlCanvas::target(uint32_t* buffer, uint32_t stride, uint32_t w, uint32_t h)
-> Result GlCanvas::target(int32_t id, uint32_t w, uint32_t h)