[youtube] Add an extractor for Youtube recommended videos (":ytrec" keyword) (closes #476)

The new extractor and YoutubeSubscriptionsIE are subclasses of YoutubeFeedsInfoExtractor, which allows to fetch videos from http://www.youtube.com/feed_ajax
ComedyCentralIE: support the extended interviews urls (fixes #1079)
Fix CollegHumorIE

Now it downloads the video over http in one file, it doesn't downloads in fragments
Added a test and use the methods in InfoExtractor for downloading webpages
Fix BreakIE

Also detect videos that come from Youtube
release 2013.07.23
CollegeHumorIE: support Youtube videos and embed urls (fixes #1094)
Mark WatIE and TF1IE as broken (related #1103)
YoutubeChannelE: switch ajax query from channel_ajax to c4_browse_ajax

It wasn't detecting when there aren't more videos
[soundcloud] Support URLs with a slash at the end (Fixes #1104)
Merge branch 'master' of github.com:rg3/youtube-dl
release 2013.07.23.1
[traileraddict] Allow all types of trailer URLs

Valid url regex for traileraddict.com is too strict. Need to allow,
e.g. theatrical-trailer, teaser-trailer, feature-read-band-trailer, etc.
[traileraddict] Obtain hd quality stream if available

No clear method for determining if hd is available so opted to just
check for presence of hd toggle function.
YoutubeIE: new algo for  length 87 (fixes #1105)

Squashed commit from the pull requests #1107, #1109 and #1110.
release 2013.07.24
Merge pull request #1113 from alexvh/master

[traileraddict] Allow all types of trailer URLs
[traileraddict]: Support clips urls and more trailer urls
Merge pull request #1114 from alexvh/traileraddict_hd

[traileraddict] Obtain hd quality stream if available

Updated md5 checksum of the test video.
Add Youtube player info for length 87
release 2013.07.24.1