More specifically, moved scale, crop, invert, desaturate and generate outline code to DrawingAlgos.gd. I am a little worried of DrawingAlgos.gd getting too big though.
A Project class contains project-specific data like name, undo_redo, frames, layers, tags and brushes. These variables have been moved from Global. This is the first step towards multiple tab support, where each tab will be a different Project.