Unable to compile all panel plugins

[Jasper Huijsmans]

Harold Aling schreef:
> "the plugins have not been updated yet."
> 
> Does this mean that the panel won't be backwards compatible?
> 

The new panel will indeed not be backwards compatible, but it is also 
not yet in SVN trunk, so this is a different problem.

The libxfce4util library headers were changed and users of this library 
should now only inlcude the libxfce4util.h, not any of the other headers.