Moving PowerDevil to kdereview

[Dario Freddi]

I've just committed a change to the Daemon. Basically, it checks on startup if 
other powermanagers are on, and asks the user through a message box if he 
wants to start PowerDevil anyway. It also exports an (empty) interface on the 
system bus to avoid double copies. Waiting for it to be standardized with a 
freedesktop spec, I think this is the best possible solution.

Cheers
Dario