Adds shortcuts:
"
J will open the Jukebox
Shift + S will open the save game menu
Shift + L will open the load saved game menu
Shift + R will restart the level
Shift + Q will quit the current game and take you back to the opening screen
Changed Alt+F4 so that it is quit the application (which is quite common with most window applications)
Also updated the strings for the dropdowns to show the shortcuts
"

Issue 1575.
Thanks, MarkL!

git-svn-id: http://corsix-th.googlecode.com/svn/trunk@2269 c39591fa-788f-11de-a72b-d90af8dea425