Certs - bugfix cert_whitelist output

* output after cert_whitelist -a or -d purported to be the whitelist entries
  for the requested course, but in fact were all of the entries in every
  course. This commit fixes that.
add undo (resub) to landing page of forum unsub link
Textbooks accessibility changes

Removed image-based textbook info from XML tutorial.

Added not about accessibility and textbooks to Building a Course file.
Bok choy tests output XUnit reports
Updated change log
Notifier re-subcribe via link

* fix assertPrefValid in tests to decrypt instead of compare
* rename unsubscribe -> set_subscribe
Don't capture the output of i18n command execution
Run an extract before running generate, so that you have all the necessary files
Upgrade the transifex client
Add a test that validates that the .po and .mo files match for all active languages
fix 2 links that were broken during i18n changes.
Release Notes 1-23-14

First Draft
Merge pull request #2264 from edx/jsa/fix-forums-links-rc

fix 2 links that were broken during i18n changes.
Modify jquery.timeago to better support i18n

Use string interpolation instead of concatenation of prefix, content,
and suffix. This is motivated by the fact that Transifex does not accept
empty strings for translation (even when pgettext is used to provide
context).
Make problem types pluggable.

This patch adds the ability for arbitrary packages to register
themselves with xmodule.x_module.ResourceTemplates as being providers of
boiler plate templates used for defining the types of problems
instructors can add to a course.  This allows third party add-ons to
define new problem types that can then be available to instructors to
use.

This patch is the result of discussion with Ned Batchelder on the right
way to approach this problem.  The solution provided here is,
admittedly, a little bit of a hack.  But the focus was on making a least
invasive fix to make something work, in anticipation that when problems
get moved into the newere XBlock architecture something a little nicer
will be in place.
BLD-364: Merge "video sources" and "download video" fields.
Make video debug messages consistent.

In the JavaScript console all messages from the Video
player should begin with "[Video info]: ". This way it
is easier to see which console.log() messages are from
the Video player, and which console.log() messages are
temporary, and should be removed before a merge/commit.
Fix video progress slider method.

In each Video JavaScript module, methods are either private,
or public. When a method is public, it is made available via
the state variable. It seems that a while ago one method
was made public, but throughout the code it is used as a private
method. This has been corrected.
Fix video code duplication.

rangeParams returned from getRangeParams() function is already
an object that contains the left and width properties. It can
be passed directly to the jQuery css() function.
Merge pull request #2274 from edx/valera/fix_video_code_duplication

Fix video code duplication.