TINYGL: Restored old drawing logic.
TINYGL: Added texture data versioning.
This is introduced to detect changes when a texture is updated.
TINYGL: Moved a check down, optimizing away a case where the pixel is ignored.
TINYGL: Added blit image versioning.
TINYGL: Fixed a bug with z buffer blitting.
TINYGL: Refined dirty region detection by adding a check on textures and blit textures version
TINYGL: Refined dirty regions redraw logic.
TINYGL: Refined rectangles merging and duplicated removal logic.