Minor changes (code format)
Fix license in some files of base library
Show timeline automatically when a new frame/layer is created (configurable option)
Timeline: Add code to show equal keyframes joined

This code is disabled at the moment because there isn't a fast way
to compare frames.
Timeline: clip and draw only necessary parts
Do not reset scroll each time we click a sprite
Update the timeline after drawing in the sprite editor (after DrawingState)
Timeline: Add proper clip to frames header and cels area
Timeline: fix scroll issues redrawing the whole widget