[youtube] Download DASH manifest

If given, download and parse the DASH manifest file, in order to get ultra-HQ formats.
Fixes #2166
Add infrastructure for paged lists

This commit allows to download pages in playlists as needed instead of all at once.
Before this commit,
    youtube-dl http://www.youtube.com/user/ANNnewsCH/videos --playlist-end 2 --skip-download
took quite some time - now it's almost instantaneous.
As an example, the youtube:user extractor has been converted.
Fixes #2175
[brightcove] Fix check for url in the result

It may have the ‘formats’ field instead of ‘url’.
[brightcove] Fix extraction of embedded videos

There was a leading ‘:’ in the regex.
The ‘flashvars’ parameter is not always available.
[mtv] Fix title for gametrailers (Fixes #2188)

We now prefer the title including the category, because that title is what is presented at the actual sites.
[mtv] Use unicode_literals
[gametrailers] Use unicode_literals

Conflicts:
	youtube_dl/extractor/gametrailers.py
Merge branch 'master' of github.com:rg3/youtube-dl

Conflicts:
	youtube_dl/extractor/mtv.py
release 2014.01.22
[servingsys] Do not run test on travis

Apparantly, even the advertisers do geoblocking now!?
From the US, this isn't outright blocked, but there are no videos returned.
[gametrailers/mtv] Fix pre-3.x compatibility function for find_xpath_attr

Fixes #2189
[hotnewhiphop] Retrieve media key
[Wimp] Use new URL relay method
[mtv] Update tests and xpath function for new title extraction
[ringtv] Fix and add news extraction
release 2014.01.22.1
[novamov] Skip tests
[d8] disable test; video got deleted
[d8] typo
[imdb:list] Switch to loading the webpage

The RSS method seems to be defunct.