small tweak to player code

I'd noticed quite a while back that Opera Mobile browser on Android played the live streams linked from the radiosai.org home page using the web player without any issues, but did not play the files chosen using the on-demand player. Checking out the code, found that the on-demand player, which is in a php file, did not have the doctype tag - the rest of the page was similar to the html page of the stream web player. Added
!DOCTYPE html
just before the html tag, and the on-demand player also started working on Opera mobile.

This change was prompted by this discussion also, along with the trial and error understanding.