Clarify that download rate is in bytes per second

I found https://github.com/rg3/youtube-dl/commit/f918ec7ea29a37521d1fc22fb9f900283c5a2c49 but it is still not clear to anyone who hasn't read Issue #723 whether the limit is in bits or bytes.  This is doubly confusing because 1) ISPs usually advertise speeds in bits per second, and 2) lowercase "k" and "m" are often used in correlation with bits rather than bytes.
Extractor for websurg.com
Merge remote-tracking branch 'upstream/master' into websurg
Improvements
Changes suggested by @phihag
Unused variable
Use self._download_webpage everywhere
[youku] Allow shortcut youku:ID and make non-matching groups non-matching (#1571)
[youtube] Adds #1312 Download annotations

Adds #1321 Download annotations from youtube
Annotations are downloaded and written to a .annotations.xml file using the https://www.youtube.com/annotations_invideo?features=1&legacy=1&video_id=$VIDEOID API.
Added unit test for annotations.
Merge pull request #1569 from Jaiz909/1321-download-annotations

Added downloading annotations download support - closes #1321
add VideoPremium.tv RTMP support
Add an extractor for Szombathelyi TV
Merge remote-tracking branch 'origin/master'
[gamespot] Fix video extraction (fixes #1587)
[tudou] Add support for youku links (Closes #1571)
Merge remote-tracking branch 'origin/master'
Merge remote-tracking branch 'Elbandi/master'
[sztvhu] Simplify
Credit @Elbandi for sztvhu
Simplify tests

* Make them directly executable again
* Move common stuff (md5, parameters) to helper
* Never import *
* General clean up