iOS device meta tags

Hi! I've added some meta tags and an icon for use on an iOS device when saved to the home screen. Also added links.js which fixes up links to the other php pages, this fools the full screen mobile safari into keeping you in full screen mode.

I made the icon myself because I couldn't find one of the right size, it isn't very good so you might want to remake it from your original sources!

We have been using these changes on our local Pi hosted Volumio for a few days and it all seems fine from a iPhone 5s running iOS 7 and a iPad mini and iPad air. 

Keep up the good work, its a great project!

r.