Use md5 checksumming to verify that we only write out xmodule asset
files whose contents differ from what we are about to write. This
minimizes thrashing of the other watchers.

Fixes LMS-452

xmodule-assets creates coffeescript files in the output directories. On
its next run, it used to delete the javascript files compiled from those
coffee files. Now it doesn't which should make coffee have to do less
work.

Fixes LMS-451

When running under watchmedo, coffee doesn't display any useful
information when it recompiles a changed file, so we make watchmedo echo
that information instead.

The preprocess task requires system and env arguments in order to
correctly load up the django environment to preprocess sass files to
inject themes.

In order for that task to recieve the arguments, all tasks that depend
on it also have to accept that same set of arguments.

This will all go away once the next evolution of themes arrives, which
will remove the preprocessing needed to inject theme names.

`rake install_prereqs` requires a minimal level of ruby and rake already
installed. If it doesn't exist, then print out a helpful message
indicating next steps.

Rake by default imports all .rake files in the rakelib dir, so we can
use that rather than doing our own import loop.

Sometimes the first click doesn't actually work, so call click up to 5 t...

Alex/fix is completed

Alex/fix rake doc

Fix for the failing acceptance tests

Cleanup pep8 violations in test_correctmap.py

Initialize MakoMiddleware manually during certificate grading runs.

Without this, problems fail to load because they can't find how to
render themselves, and the certificate generation grading run will
get an inaccurately low count of the possible points a user could
get (anything they didn't see will be omitted), inflating their
grade during certificate calculation and making it inconsistent
with their Progress page.

Clean up assets page notifications

Remove hack to work around multiple notification click issues -- and actually resolve
the issue so that the hack isn't necessary

Fix test_system looking like a test to nosetest. Fix class inheritance causing double counting of coverage.

Instrument sequentials with segment-io

Refactor Backbone notifications

pep8 changes made during long refactoring

Fix a bug in diff-cover