Add command line options to
- Open the URLs in a separate window (--open, -o)
- Merge the events of the URLs into the standard calendar (--merge, -m)
- Add the URLs as new resources (--import, -i)
If no command line option is given, korganizer will ask which of these actions should be taken for each URL. If no URL is given, the standard resource calendar is displayed.

This commit will probably also remove the need for korganizer-import.desktop (but I don't know the details why that was added at all, so I don't remove it myself).

Unfortunately, this fixes the problems only for standalone KOrganizer, not when the calendarpart of kontact is loaded. In that case, none of the options has any effect (as koapp.cpp is not used in kontact). I don't know kuniqueapplication enough to determine what i have to change to make the calendar part of kontact behave similar to korganizer standalone...