HTML Validaiton server is getting 502 errors...
HTML Validaiton server is getting 502 errors...

This change makes that test optional, and
fixes #98

zen-audio-player/zen-audio-player.github.io,divayprakash/zen-audio-player.github.io,divayprakash/zen-audio-player.github.io,monicacheung/zen-audio-player.github.io,Ab1d/zen-audio-player.github.io,zen-audio-player/zen-audio-player.github.io,monicacheung/zen-audio-player.github.io,Ab1d/zen-audio-player.github.io