added "hide from status bar" option
Merge branch 'master' of https://github.com/alberti42/iTunes-Volume-Control into hide-from-status-bar

Conflicts:
	iTunes Volume Control/AppDelegate.h
	iTunes Volume Control/AppDelegate.m
	iTunes Volume Control/en.lproj/MainMenu.xib
added explanatory popover for hide-from-status-bar option
Including new modifications with popover