Fixed issue #1277 KeyError when no description.

Allows a continue with a warning when an extractor cannot retrieve a description.
added kickstarter IE
[canalplust] accept urls that don't include the video id (fixes #1415), extract more info and update test
[youtube] update algo for length 82 (fixes #1416)
[gamespot] Update test video title
Merge pull request #1350 from Jaiz909/description-keyerror-fix

Fixed issue #1277 KeyError when no description.
Merge pull request #1409 from JohnyMoSwag/master (closes #1404)

added kickstarter IE
Merge pull request #1413 from tewe/master

Add Ustream channel support
[ustream] Simplify channel extraction

the ChannelParser has been moved to a new function in utils get_meta_content
Instead of the SocialStreamParser now it uses a regex
XHamsterIE: Add support for new URL format
[googleplus] Fix upload date extraction
Now --all-sub is a modifier to --write-sub and --write-auto-sub (closes #1412)

For keeping backwards compatibility --all-sub sets --write-sub if --write-auto-sub is not given
[mixcloud] Rewrite extractor (fixes #278)
Set the ext field for each format
[soundcloud] Add an extractor for users (closes #1426)
[youtube] support youtube.googleapis.com/v/* urls (fixes #1425)
Merge pull request #1422 from rzhxeo/xhamster

XHamsterIE: Add support for new URL format (download in hd by default)
[youku] better error handling

blocked videos used to cause death by TypeError, now we report what the
server says