Add '' default to bodyclass in courseware templates

This prevents from having a 'None' CSS class in the <body> tag when no
css_class is defined for the course.
fix typo in the data docs readme file
Add Matt Bachmann to authors file
Remove warning about LTI not working in Preview mode
adding db overrides to aws_migrate.py
remove check for PASS
adding check back in
check for None so an empty string is valid for a password
adding DB_MIGRATION_ENGINE and fixing defaults
fixing syntax
Prepend theme template paths

Allow templates override.
Make assets:coffee a dependency of i18n:extract

Extraction is done on the compiled .js files, so coffee compilation
should be done before extracting strings.
don't show the add response button if responses are not allowed.

JIRA: FOR-452
added back in component header visual separation from component rendering block, making clear the display name for each component is not rendered to students
MixedModulestore wraps most getters, update_item, delete_item
with code to translate between addressing schemes based on app
and persistence layer addressing scheme specification.

STUD-1206
Added test for defaulting use_locations
Merge pull request #2446 from edx/rc/2014-02-05

rc/2014-02-05
update_item and other refactorings continued
Clean up Mongo databases created by the test suite.
Stop using JavaScript to set the body CSS class

This prevents everything from blinking, since the CSS class will be
present when the page is rendering.