Make errors more generic. It won't always be "video"

[sirlancelot]

If an error occurs while trying to play an audio file, I still get the generic "The video could not be loaded, either because the server or network failed or because the format is not supported." error message. Since video.js can play audio files as well, "video" should be changed to "media" or similar.

[mmcc]

Ah good point, it's pretty easy to forget about the audio-only use case. Interested in putting a PR together to make the messages more generic?

[gkatsev]

PRed and fixed.