Fix multiple video device test

two-video-devices/index.html does do what it's supposed too, it uses the same camera for different video tags.

I fixed it by creating a new page and named it appropriately where It now iterates through the devices enumerated via getSources if available and displays them in individual video tags.

If the onended event is fired it's displayed on the page in red. It will happen quite regularly if you have many cameras connected to the same machine sharing the same USB bus/hub. 

Note that this is not a pretty page by any means but it gets the job done, did not want to spend to much time on it.

Fixes #203.
Nit: in general, to improve page load speed, put scripts at end of doc (before closing body tag).