Warn when creating repository in special folder, such as Desktop

Create Repository menu item is probably clicked by mistake, which is not supposed to do so in such folder

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Make sure folder string is not empty

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Merge branch 'repocreate'