Twenty Fourteen: changes to JavaScript files to pass `jshint`, props jorbin. Fixes #25908 #25909 #25910.

 * Add global variable flags to top of JS files.
 * Group variable declarations correctly.
Built from https://develop.svn.wordpress.org/trunk@26084


git-svn-id: http://core.svn.wordpress.org/trunk@26004 1a063a9b-81f0-0310-95a4-ce76da25c4cd