Added trailing slashes otherwise the course_id regex sometimes eats up get parameters.

LMS-2738
Get rid of skiptests
Split mongo correctly serializes and deserialized references
STUD-1592, STUD-1603, LMS-2642
Add tests for has_course
and negative tests for get_course.
BLD-725: ChoiceGroup i18n.
Fix exception on Internet Explorer when adding first transcript language

Internet Explorer throws an "Invalid argument" exception when uses an empty string as the parameter in ```namedItem``` method.
Change empty string into null value can maintain browser consistency.
Do not persist anonymous ids when exporting for all students of a course.

For large courses this causes export to take a long time and to time out.

LMS-2747
Merge pull request #3901 from edx/dhm/opaque-dont-skip

Dhm/opaque dont skip
Merge pull request #3900 from edx/dhm/test_has_course

Add tests for has_course
i18n of Image Response [BLD-723]
Parse urls with query params for ^/static

  Query params with a value that starts with /static should have their values converted to the full location.
  Query params with a value that does not start with /static should be left unchanged.
Merge pull request #3897 from edx/jmclaus/i18n_image_response

i18n of Image Response [BLD-723]
Merge pull request #3394 from edx/dcadams/parse_query_params

Parse urls with query params for ^/static
DOC-362, another set of students who don't get email
Two image references incorrectly preceded by a comment
Merge pull request #3910 from edx/ahodges/documentation/images

Two image references incorrectly preceded by a comment
Build 'window.location.origin' for Internet Explorer

As TinyMCE's CodeMirror plug-in uses 'window.location.origin' which is not supported by Internet Explorer, the HTML or raw code editor does not work under Internet Explorer.
We need to create one in order to make these vendor codes work under Internet Explorer.
BLD-1103: Fix ChoiceTextResponse.
Merge pull request #3902 from edx/anton/i18n-choice-group

ChoiceGroup  i18n.
Merge pull request #3879 from edx/usman/lms2747-anonymous-ids-collection

Do not persist anonymous ids when exporting for all students of a course.