For content not supported in a browser (or in Flash), show a user-friendly error message

[jrw95]

Found during testing of IE9/Firefox on Windows 7.

STR:

1. In the sample videojs index.html page, replace the source URLs with URLs to various other content types, or remove all except the specific content type under test. For example, to test OGG support, make a copy of the index.html.example page, and remove the MP4 and WebM URLs.
2. Load the desired test page in the target browser. For example, I wanted to test OGG support (or lack thereof) in IE9, so I loaded the copy of index.html.example that contained only a URL to oceans-clip.ogv.

Expected:
If the content type is not supported in a particular browser (or in Flash), a user-friendly error message is displayed.

Actual:
In most cases, I saw the video.js player, with some messaging around it for Google Chrome and Adobe Flash. In other cases, clicking the play overlay just did nothing.