solve failed comp LXQT with LXQt (OnlyShowIn=LXQt;) in desktop files
Make desktop enviroment names comparisons case insensitive

This is the follow up of commit 4cec687127adb1e96cc5b725eabe6a1188c4c873
by Alf Gaida <agaida@siduction.org>
detectDesktopEnviroment() returns uppercase, so we convert the user
supplied environment name to uppercase.

Signed-off-by: Luís Pereira <luis.artur.pereira@gmail.com>
Updates some XdgDesktopFile methods documentation

Signed-off-by: Luís Pereira <luis.artur.pereira@gmail.com>
Merge branch 'compare-desktop-environments'

* compare-desktop-environments:
  Updates some XdgDesktopFile methods documentation
  Make desktop enviroment names comparisons case insensitive
  solve failed comp LXQT with LXQt (OnlyShowIn=LXQt;) in desktop files