Improve gnome-osd-properties

[Martin von Wittich]

1) The properties dialog is not available under System > Preferences, but has to be launched from a command line.

2) The 'hide timeout' value can atm only be set with gconftool-2, e.g. gconftool-2 -s -t int /apps/gnome-osd/hide_timeout 500. This should be included in the properties dialog.

3) The colors can't be changed from the properties dialog; the default color seems to be hardcoded.

4) The test message is too long :)

5) When you uncheck Notifications -> 'Notify on IRC messages directed to me', the checkbox 'Include message text' is grayed out. When you now close and reopen the properties dialog, the first checkbox stays unchecked but the second checkbox is again enabled and toggle-able.