Use VERSION defined at config.h
Use static qualifier
Extract preference menu dialog code
Add prototype to header file
Add missing variable declaration
Use GTK dialog instead of using GTK window directly
Remove unused code
Include copyright header
Use utility funcion to add copyright tab
Remove unused code
Update submodule
Support debug build
Support silent build

If you want to use verbose build, use make V=1
Use verbose mode
Update copying
Update NEWS entry