Instead of having a frame_duration[] array in the Project class. This makes the code much more readable and understandable, using less lines of code and, by avoiding an extra array, we also avoid potential out-of-bound array crashes.
The functionality for the user has not changed, and by testing so far I didn't find any issues.
It now first attempts to serialize the project data and turn them to JSON, and then opens the file. This is a lto safer because, if a crash happens in the serialization, the file is not already open, and therefore it does not get corrupt. Earlier, if a crash happened, the file would be empty. This meant that if that file existed previously, all of the data would be lost.
* Sync for my local files to my repository
* This is frame properties update, it works but I can't be stored while
saving or loading and that makes crashes just the beggining :)
* I forgot this files :P
* Frame Properties update.
* Updating frame properties
* Update Translations.pot
* Changes to CanvasPreview and CelButton change
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.
The Canvas is now single node, instead of having multiple canvases for each frame. This should also be a performance optimization, since there are less canvas nodes, so there are less _input() calls. It should also fix a rare Undo/Redo issue with motion drawing and making lines. Could be unstable, needs more testing.
As a side effect, the guides are now the same for all frames, so this should also close #246.
Replaces nested Global.animation_tags arrays. Also replaced array.duplicate(true) with looping through the array and creating a new class for each array element, because duplicate(true) does not create new classes, unfortunately, which was causing issues with undo/redo.
Moved code from Global.gd and Canvas.gd to DrawingAlgos.gd. Will also move the fill_gaps and draw_brush methods of Canvas.gd next. Maybe even refactor the inside of them a bit to make them easier to read.
Removed separators entirely. Also made the AnimationTimeline have a StyleBoxFlat of its own, which we use to expand its margin top to cover the little space left because of the VSplitContainer. We also use a TextureRect as a fake VSplitContainer grabber.
