Don't show zero length messages
Don't show zero length messages

This may cause developer confusion, but it is a programmer bug to try and display a message that is nothing. Let's not confuse the user with a blank message.
hlung/MTStatusBarOverlay,JinlianWang/MTStatusBarOverlay,Haraguroicha/MTStatusBarOverlay,ovuline/MTStatusBarOverlay,Slepter/MTStatusBarOverlay,myell0w/MTStatusBarOverlay,coneybeare/MTStatusBarOverlay,PocketScientists/MTStatusBarOverlay