Better hls example

[machenmusik]

Per discussion on #3210.

[ngokevin]

Sweet! Found a few issues just now:

• Clicking the window causes video to pause (in case of mouse drag).
• First time loading, I got a DOM timing issue that play() call was interrupted by a pause() call.
• Sometimes WebGL errors when the video not yet loaded and gets passed to WebGL and we have a texture with no image.

[machenmusik]

re: clicking - I can remove the toggling and just make click trigger play, to fix that.
re: first time DOM timing issue and WebGL errors - can you say more about your configuration / browser at the time? always, or intermittent? main page, or detail?

[machenmusik]

OK I think those issues are addressed now

• click to play only, no toggling to avoid pause on mouse drag, etc.
• for main page, which uses MP4 and may not be streaming, don't shorten the a-assets timeout

https://github.com/chenzlabs/aframe-360-video-example