Dailymotion expando support

Requested in #1096.

These expandos work great, *but* they produce about a million [mixed-content warnings and errors](https://cloud.githubusercontent.com/assets/7673145/5063324/ace7bba2-6daf-11e4-814e-b653ddbfba26.PNG) (the errors aren't enough to stop playback, just logging scripts and other unimportant stuff). I'm not sure if that's a deal breaker.