(cherry picked from commit 14100ba1)

(cherry picked from commit 832da3ad)

(cherry picked from commit 050846af)

(cherry picked from commit 664efb98)

(cherry picked from commit a17bf5e2)

(cherry picked from commit 273df4e1)

(cherry picked from commit c96511a2)

(cherry picked from commit 1511ec84)

(cherry picked from commit d2554909)

This was 7b7a3427, which became an empty commit after we rewrote history to
remove 42650ab3c.

* In addition to the JABBER settings, now we want to be sure to get
  DATABASE_ROUTERS, too.

Conflicts:
	lms/envs/common.py

Merge remote-tracking branch 'origin/feature/nate/simple-chat' into edx-west/release-candidate-20130613

Conflicts:
	lms/templates/courseware/accordion.html
	lms/templates/courseware/course_navigation.html
	lms/templates/courseware/progress.html
	lms/templates/navigation.html

/dev/random blocks if there is not enough entropy to return the
requested number of bytes, and this turns out to hang our AWS
servers. When generating random bytes for Jabber passwords, use
/dev/urandom instead. We figure that this will be "secure enough,"
since we'll have bigger problems if someone manages to get ahold
of our /dev/urandom's seed value.

Add utilities to the Jabber app to parse the Jabber settings and
build the URLs, chat room names, and user passwords for connecting
to ejabberd. This is a WIP commit since it still needs tests (in
progress...stubbed out with comments).

In the initial theming pass, we missed two error pages. This commit
replaces edX values with PLATFORM_NAME and TECH_SUPPORT_EMAIL
settings.

When chat is enabled, sync user accounts with the ejabberd server
by directly writing into its MySQL database. This is ugly in the
sense that ejabberd just does a simple string comparison when
authenticating a password against a username, so we have to send
passwords in the clear in the templates. In a future commit, I'll
implement a password rotation mechanism to make this slightly more
robust: currently, everyone's password is just a dummy string.

To enable this, you'll have to add a 'jabber' key into your
DATABASES dict in the settings, and point at an actual ejabberd's
MySQL instance. The current plan is to just point at one that we've
got set up, since running ejabberd locally (not to mention on
MySQL instead of Mnesia) is non-trivial.

Rather than checking to see if the JABBER_DOMAIN is not set and
continuing on, bail with an ImproperlyConfigured exception as soon
as we notice its absence.

Per
https://edx-wiki.atlassian.net/wiki/pages/viewpage.action?spaceKey=ENG&title=I18n+coding+guidelines
ensure that chat messages are properly internationalized.

Only render the chat widget if both the site has enabled it in the
`MITX_FEATURES` and if the course has enabled it. In addition, fail
gracefully with a log warning if the `JABBER_DOMAIN` is not set, and
do not try to render the widget. However, do go ahead and render the
rest of the courseware.

To protect against chat blowing things up, we include a way to
enable and disable it on an entire site-wide basis.

Ensure that the chat connection settings are generated properly for
the template context.

jQuery already available across the whole site at the top level, so
no need to include it again specifically for the chat widget.

Embed a chat widget (much like the calculator widget) into the
courseware. To use, you must point it at an ejabberd box,
configured as `JABBER_DOMAIN` in the settings.

Fix typo and an unclear description.

[STUD-256] Seems like on chrome when cancel is hit in the file chooser, the 'change...

Fix broken lettuce tests

Feature/dhm/timeconv

Update lettuce test for problems with new css for show and hide answers.

Seems like on chrome when cancel is hit in the file chooser, the 'changed' event is fired and startUpload() was being called. We need to check to see if the upload file is blank and - if so - just return immediately out of the function