Reworking the editor. Factorize code and improve MVC.
Continuing to improve the code of the editor.
Merge branch 'solarus-1.0.0' into editor_project_db
Editor: allow to edit project_db.dat from the GUI (experimental).
Stabilizing the editor.
Fixing the editor.
This class is no longer used.
Editor: fix concurrent modification of projest observers
Editor: expand maps in the quest tree initially.
Editor: improve initial size of components.
Editor: don't ask to save if there were no modifications.