Translating key names in GTK+

[Matthias Clasen <mclasen redhat com>]

I have just committed a fix for
http://bugzilla.gnome.org/show_bug.cgi?id=300224
to GTK+ head. This adds a number of new translatable strings for 
key names to GTK+. They all use Q_() and have an easily recognizable 
context string:

keyboard label|Delete
keyboard label|Insert

I have not marked all key names for translations, since that
would add many pointless strings to the pot file. If you notice
a keyname that is not marked for translation, but should be,
please tell me.

Also note that I took the occasion to add the "keyboard label|"
prefix to the modifier names ("Alt", "Ctrl", "Shift") as well,
so their translations will probably be fuzzy now.

I plan to do an unstable GTK+ release by the end of next week.

Matthias