Fix string extraction error in underscore files

Pass standard list of xblock mixins to MixedModulestore in tests

Entrance exam gating

The written style ```interpolate(gettext('some text'), {...}, ...)``` will will cause the string inside gettext() not be extracted.
So a separate line is needed for ```gettext``` when gettext function is directly called inside a call to the interpolate function.

added READMEs for top level directories

- added entrance exam check on course info
- staff can by pass gating and added tests
- refined gating logic
- changes after rebasing with Asad's branch
- check ENTRANCE_EXAMS feature is enabled
- updated test to reflect new logic
- catering anonymous user in entrance exam permission
- fixed broken tests
- change after feedback on 16/3
- fix for a broken test
- created new entrance_exams module
- fixed quality error and improved test coverage
- put get_required_content back in milestones helper
- Refactored entrance exams logic
- Refactored tabs logic
- Fixed broken unit test
- changes after feedback from dan-f on 3/27
- removed unnecessary user.is_anonymous check
- Addressed PR feedback
- Addressed commit-specific feedback
- Rework guard clauses
- Add coverage for course info case

Fixed i18n Problem with xBlock Menu

Convert Vertical XModule to pure Vertical XBlock.

mattdrayer/SOL-461: Student dashboard clean-up

Remove timer_expiration_duration (leftover from Pearson proctored exams)

Fix two missing replacements of {studio_name}

Located in ```howitworks.html``` and ```import.html```.

Addressed bug in the following issue:
https://openedx.atlassian.net/browse/TNL-1296?filter=12810

There were strings that were not i18n in the xblock problem menu. The fix I made seems a little hacky. The yaml files controlled what the titles ended up being in menu. Since yaml has no i18n capabilities, and since mako does not allow for hashtables (unless they are introduced from the function/class that renders them) the commit I made was the best solution I could think of. If you know how to introduce i18n strings into yaml files or where this file is being rendered so I can pass in a hashtable that would be great! More discussion/information on this issue can be found in the issue thread linked above.

Observe bad behavior:
1. Load Studio.
2. Log in as staff@example.com.
3. Click "Content" and go to "Outline" in the dropdown.
4. In Example Week 1 click on "Homework."
5. Click on any question from the dropdown.
6. Click on "Problem."
7. Clicking on both "Common Problem Types" and "Advanced," notice how some options are not i18n.

~Please keep this webpage open after viewing the bad results~

View Correction:
1. Put my code into your edx-platform folder.
2. Kill the studio process.
3. While logged in as edxapp enter the following into your commandline:
paver i18n_extract && paver i18n_dummy && paver i18n_generate && paver devstack studio
4. Reload the studio page and notice how the strings are in the correct i18n format.

Fixed i18n Problem with xBlock Menu

Addressed bug in the following issue:
https://openedx.atlassian.net/browse/TNL-1296?filter=12810

There were strings that were not i18n in the xblock problem menu. The fix I made seems a little hacky. The yaml files controlled what the titles ended up being in menu. Since yaml has no i18n capabilities, and since mako does not allow for hashtables (unless they are introduced from the function/class that renders them) the commit I made was the best solution I could think of. If you know how to introduce i18n strings into yaml files or where this file is being rendered so I can pass in a hashtable that would be great! More discussion/information on this issue can be found in the issue thread linked above.

Observe bad behavior:
1. Load Studio.
2. Log in as staff@example.com.
3. Click "Content" and go to "Outline" in the dropdown.
4. In Example Week 1 click on "Homework."
5. Click on any question from the dropdown.
6. Click on "Problem."
7. Clicking on both "Common Problem Types" and "Advanced," notice how some options are not i18n.

~Please keep this webpage open after viewing the bad results~

View Correction:
1. Put my code into your edx-platform folder.
2. Kill the studio process.
3. While logged in as edxapp enter the following into your commandline:
paver i18n_extract && paver i18n_dummy && paver i18n_generate && paver devstack studio
4. Reload the studio page and notice how the strings are in the correct i18n format.

Update add-xblock-component-menu-problem.underscore

Reverted File

Modified capa_base.py to make Blank Advanced Problem i18n

Make LMS base gray AA compliant

Record durations of xblock views and handlers

Update course_publish event actions - Logged SOL-611 for follow up work 

Add John Espinosa to AUTHORS

Fix error when STUDIO_NAME uses non-ascii characters

Fix code comment showing in rendered page

Update translations (autogenerated message)

View discussion of user profile return 404

Added Myself To The Authors List

The replacement strings need to be unicode, so that when STUDIO_NAME contains non-ascii characters python can handle it correctly without raising exceptions.
Also, the value of STUDIO_SHORT_NAME can be read from cms.env.json.