Add extra_info argument to extract_info and process_ie_result

It allows to update the info_dicts with other values

(closes #840)
MyVideoIE: add rtmp support
UstreamIE: get thumbnail and uploader name
Add support for Howcast.com - closes #835
Add support for Vine - closes #845
VineIE: extract more information and minor style changes
HowcastIE: extract thumbnail
Merge pull request #842 - myvideo, rtmp support

@dersphere code, from dersphere/plugin.video.myvideo_de.git
rewritten by @mc2avr
released in the Public Domain by the author
ref: https://github.com/rg3/youtube-dl/pull/842
make rtmpdump inherit the verbose option for debugging
Python 2 compat fixes for MyVideo.de rtmpdump downloads
add support for Flickr videos - closes #261
Add TeamcocoIE (closes #212)
small tweaks
Fix HowCast IE
release 2013.05.23
BlipTV: accept urls in the format http://a.blip.tv/api.swf#{id} (closes #857)

Tweak the regex so that BlipTV can be before BlipTVUser.
YoutubeIE: fallback to automatic captions when subtitles aren't found (closes #843)

Also modify test_youtube_subtitles to support running the tests in any order.
Merge pull request #854 from rg3/youtube_automatic_captions

YoutubeIE: fallback to automatic captions when subtitles aren't found
Add tests for justin.tv and twitch.tv
Fixed an error downloading vimeo pro videos.