Remove HTTP provider, add startparam to video

[jeroen]

For a next major release of the player, we should investigate removing the HTTP provider altogether. This is especially useful if we're going for a more built-in bitrate switching / hd plugin.

The nice part left of this provider is then the startparam option. Without all bitrate switching logic, this is fairly straightforward though and can be added into the Video model.

This will also ease support, since there's only 2 Flash video providers to debug (RTMP and Video) instead of 3.