- Adding default value in empty frames to avoid artifact when paint
bucketing (you may have issues with previously stored model before this
commit, no migration plan for papybrossette :D)
- Fix issue: Model does not show up when loading a remote GAE model
- Removing FRAMESHEET_UPDATED events (remains of history manager
implementation)
Partial cleanup of piskel:
new events and constant
move palette and color picker in ToolSelector
create Notifcation.js and move user message in it
create LocalStorageService and move LS stuff in it
