F_intro

This pull request will be to merge the work completed in f_intro into develop.

f_intro handles the addition of a "intro" screen that consists of the company logo and a bear roar sound snippit being played before the menu appears. 
The logo fades from transparent black to visible over a couple of seconds, then stays visible for a second where the bear roar sound is played, finally it fades back to black transparent over a couple of seconds then moving on to displaying the menu.
The intro is not skippable
Maybe some of this should run off the back of a timer rather than relying on clock ticks?