Certificates: Add regeneration command

* Adds regenerate_user command, which lets you run certificates for one
  particular user in one particular class, regardless of whether they
  have a pre-existing certificate.
password reset pages use Django templates, not Mako
Release email script: use --no-pager
Add neglected entries
Use known translation if exists to get groupname
Merge pull request #1435 from edx/rc/2013-10-23-fixes

release candidate improvements
use bleach instead of lxml.html.clean for sanitize_html OEE
Convert checklists to new URL scheme.
Do need context_course variable for segment io.
optimize keyboard focus management on dashboard's modals

add license to a11y_tools.js

add tests, some reorganization of js tests

skip "toBeFocused" tests for now
Fixed a bug where legacy instructor dash's email editor failed to load
Fixed indentation
LMS: adds correct css/style assets back to password reset and confirm views
Test that instructors can access courses
Remove as_old_location methods
They were incorrect if there were periods in the org or name.
Merge pull request #1401 from edx/adam/a11y-modal-management

optimize keyboard focus management on dashboard's modals
Indicate active status more clearly for people
with vision impairments

* bold text when active
* add in some extra text for screen readers

LMS-1306
Add cache-based locking to subtasks to ensure that the same task is not running in two workers at the same time.
Add cache-based locking to subtasks to ensure that the same task is not running in two workers at the same time.
Add Timed Transcripts Editor.