Fix menu item capitalization & typography

[virtualritz]

Menu items do not follow platform capitalization rules.

On both Darwin, Windows and most *Nix desktops, some simple rules apply:

• English Headline Capitalization
• The last word is always Capitalized (e.g 'Check for Updates')
• If an item requires further input before the app can perform an action this must be indicated with an ellipsis character (…) at the end (e.g Save As…)

The whole 'Add' menu needs to be reviewed for this.

See also: https://developer.apple.com/library/mac/documentation/UserExperience/Conceptual/OSXHIGuidelines/TerminologyWording.html#//apple_ref/doc/uid/20000957-CH15-SW4