getting seen in the settings manager

[Brian J. Tarricone]

Hey guys,

Currently xfce4-settings-manager will only show apps that have
X-XfceSettingsDialog in Categories in their .desktop file.  This has
annoyed me since I first did it, because it's lame.

We already use our special non-standard X-XFCE category all over the
place.  Would it make sense to ditch X-XfceSettingsDialog entirely, and
key off "X-XFCE" + the (standard) "DesktopSettings"?

If no objections, I'll make this change in the settings manager
sometime soon.  Most of the dialogs already have those two categories,
and X-XfceSettingsDialog can be removed at your leisure.

	-b