Fix up the excluded extensions bit.

This adds the missing admin class, and registration of it, required to
actually change the value of the excluded extensions configuration.

Bump ORA version to 0.2.7.

Get tests running successfully on CircleCI

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

Move markup helpers to djangolib

Move JSON samples out of translated strings so translators can't make mistakes

Don't use using() in migrations

Correctly set certificate status for audit certs when regenerating.

Bump hash for problem builder

COR-2403

Upgrade Django from 1.8.7 to 1.8.9

Update translations (autogenerated message)

Correctly format date block dates.

Remove unused MULTIPLE_ENROLLMENT_ROLES feature setting

bookmark button js caching

LMS: darkening a gray on the profile page

Do not flush the database when using bok-choy in testsonly mode.

TNL-3954

Testsonly will not work currently, because the database flush will
remove some data fixtures. Even when they are loaded at the beginning
of the next test run, there are database corruptions. Instead of
flushing, do not do anything with the database at the end of the
testsonly test run. That way, tests that use dynamic data can be
run many times in a row.

Fix - skip orphans from content group usage information for split

Refactor Block Cache to separate Collect and Transform phases

Refactor js_util helpers

- Rename escape_json_dumps to dump_js_escaped_json
- Rename escape_js_string to js_escaped_string
- Update js_escaped_string to output empty string for None
- Introduce dump_html_escaped_json
- Move dump_js_escaped_json after the pipe as new best practice
- Introduce additional uses of helpers
- Introduce new djangolib directory and move js_utils

MA-1368

Remove skip from studio page bok choy test