Added Cask for FnFlip, a Prefpane for managing your Fn keys.

>FunctionFlip individually controls your MacBook or MacBook Pro's
function keys, turning special keys back to regular F-keys, or vice-
versa. FunctionFlip is a preference pane; you'll find it in the "Other"
category in System Preferences.

http://kevingessner.com/software/functionflip/