Fourteen Colors: update coloring of media elements (audio and video players) to adapt to Twenty Fourteen's implementation of the Genericons styling. Add two new hooks to allow devs to filter the Fourteen Colors output CSS, so that custom additions/modifications can be saved & cached with the core Fourteen Colors CSS.

git-svn-id: https://plugins.svn.wordpress.org/fourteen-colors/trunk@978310 b8457f37-d9ea-0310-8a92-e5e31aec5664