use Title-Style Capitalization for menu items.
References:
on OSX: https://developer.apple.com/library/mac/documentation/userexperience/conceptual/applehiguidelines/TextStyle/TextStyle.html#//apple_ref/doc/uid/TP30000365-BABDIBBH
on MS Windows: http://msdn.microsoft.com/en-us/library/windows/desktop/bb246428%28v=vs.85%29.aspx
Merge branch 'workshop' of https://github.com/MrKepzie/Powiter into workshop