FormSettings: show Discard button only in Debug mode. Update hint text.
FormSettings: fix minor "jumping" of button row when hint text appears or disappears
Merge pull request #1859 from feinstaub/fix_remove_discard_button

FormSettings: show Discard button only in Debug mode
Merge remote-tracking branch 'origin/master' into feature/DistSettings

Conflicts:
	GitUI/CommandsDialogs/FormSettings.Designer.cs