Add section headings to test console output

i18n tests generate XUnit reports

Move i18n and docs test commands out of tests.rake

ConfigurationModels can be managed using the admin site. They are
append-only, and track the user who is making the change, and the time
that the change was made. The configuration is stored in the database,
and cached for performance.

[LMS-1220]

LMS-1963

[LMS-1614]

Refactor rake tasks for acceptance tests
Address PR comments

This explains why acceptance_static is used

Acceptance_static is used to prevent collect static from using a seed
test.py had its seed removed due to redundancy

This allows the build to pass in Jenkins

This allows the build to pass in Jenkins

directory is created before it is cleaned.

Added test cleaning to fasttest_* instead of test_*, so that
it always gets executed for lms and cms tests.

Added comment to `directory` command for tests.rake

Separated cleaning of test fixtures from cleaning of reports
directory to resolve conflicts with collectstatic.

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

Removed cleaning of reports folders, since this was
interferring with coverage reports generated
sequentially by rake test.

We used to specify specific rake test tasks so that we could run all of
them even if early ones failed. However, that meant that as new tasks
were added, they weren't being run on jenkins.

Now, there is a facility in the rake scripts so that tests can run using
the test_sh function, which will delay failure until the end of the rake
run, unless the TESTS_FAIL_FAST environment variable is set.

Furthermore, this reorganizes the jasmine test tasks so that we can run
those as part of `rake test` as well.

Added comments to tests.rake