Now we have three modes: normal mode (everything is visible), the first
intermediate mode (context bar+sprite editor+timeline), and advanced mode
(sprite editor only).
- Add HAVE_CONFIG_H wrapper to #include "config.h"
- Removed widgets namespace (it's in app now)
- Move some functions from src/file/file.h to src/base/cfile.h
- Move Vector2d to base library
- Rename MenuItem2 to AppMenuItem