Cloning kit may get name already in use

1. Start Creator with empty settings.
2. Go to "Tools" -> "Options..." -> "Build & Run" -> "Kits".
   There should be one kit named "Desktop" which is the default.
3. Select kit "Desktop".
4. Click the "Clone" button.
   Creator creates a kit named "Clone of Desktop".
5. Select kit "Desktop" again.
6. Click the "Clone" button again.
   Creator creates another kit named "Clone of Desktop" and displays a warning about it.

Creator should not use names which are already in use, e.g. it could use an index instead.