When replicating CourseEnrollment, make sure Users were created in all DBs before replicating other models

fix another backcompat html bug

Added fix for answer status and show answer to stay in the same place

BUG SMASH

{} -> {0} etc in .format statements

fix html rendering bug

Fix backcompat_module : html escape & py26

Hide chapters in addition to sections

Add facility for fixed number of problem attempts

Made video go to the center of the screen in full screen

Move mitxmako out of common lib, and pass template rendering function in...

Feature/halogenandtoast/multiple textbooks

MAnage askbot images

Fix bug preventing comments from being in course.xml

Feature/victor/strip metadata

* course roots live in roots/{url_name}.xml
   - one is linked from course.xml

* policies live in policies/url_name.json
  - loaded based on course url_name

* Updated to pass policy through into xml parsing, so it takes effect
  before descriptor constructors are called.

* Update toy test course to new structure, fix up tests

* the former does a fallback if metadata['display_name'] isn't set.

Added styles to grade out the top and bottom of the sidebar border and f...