[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
[soundcloud]: Some improvements

Extract thumbnails.
Make SoundcloudSetIE a subclass of SoundcloudIE to reuse some code.
Directly extract the file url without downloading an extra page.
ExfmIE: extract Soundcloud songs using SoundcloudIE

Now SouncloudIE accepts api urls.
YoutubePlaylistIE: break only if there's no entry field in the response

Otherwise the Favorite videos playlist cannot be downloaded complete.
Also break if it reach the maximum value of the start-index.
YoutubeIE: Move the code from _real_initialize to a base class

This allows to reuse the code in other IEs without having to overwrite some parts.
Add an extractor for downloading the Youtube favorite videos(closes #127)
release 2013.07.24.2
[youtube] add an extractor for the "Watch Later" list
[youtube] use itertools.count instead of a "while True" loop and a manual counter
Added an option 'e' to go with 'video' or 'embed'

Based on links that I've seen, /e/<videoid> also occurs in the wild, and making this substitution yields effective results.
changed video_url regex

Some older videos contain an extra properties such as 'embed' before 'type'.
[ina] Fix URL detection (Fixes #1121)