This now correctly migrates and dumps files for both databases.

Run lettuce migrations for both databases

This is a clone (copy) of CSMH's declaration and methods with an added
id of UnsignedBigInAutoField

We should be able to delete the save_history code, but needs testing.

Add error logging when capa failures happen

Put StudentModuleHistory into its own database

Bump out the primary key on CSMHE

This gives us a gap to backfill as needed.
Since the new table's pk is an unsigned bigint, even for people who don't
consolidate CSMH into CSMHE, the lost rows are unlikely to matter.

Remove StudentModuleHistory cleaner

It also contains the lettuce caches.

Sass compilation is no longer dependent on Ruby, so we are
removing its dependencies.

Other small changes:
* output the list of installed python packages
* tee the pylint output to the console so the build doesn't timeout when computing violations

This will ensure a clean database for new runs, and will likewise
allow for the serversonly / testsonly approach for developing
bok-choy acceptance tests. The cleaner model will completely
rebuild the edxtest database for any new test run. This will
not be a costly maneuver because of our test cache.

There's no need to use a string literal in setattr, delattr, or the
two-argument form of getattr.

This is a partial revert from d8fd8ed6

Please note that this is a squshed commit and the work of:
Symbolist, macdiesel, nedbat, doctoryes, muzaffaryousaf and muhammad-ammar

This includes:
* Ability to specify number of processes to run bok-choy tests in
* A forked nose commit to get the multiprocess plugin's logging to work
* A different plugin (xunitmp) must be used for pulling together xunit results

This works by:
* Starting the various servers that are needed for the acceptance test environment
* Running the tests themselves in multiprocess mode

In the event of a pylint failure, we need to cat the log. This will also
ensure that the remaining scripts in the job can run.

The jenkins-common script is the better place for this particular setup, since that
script is doing similar setup steps to prepare the environment for running
various tests/subsequent scripts. This also will resolve downstream processes,
such as our jenkins AMI builder (for jenkins-worker images).

Note that because js testing occurs on a different CI job than python
unit testing, files will not be clobbered by this change. The python unit
testing job also creates the same-named report through the diff_coverage
task.

The latest version is compatible with the new coverage.py.