make embargo template theme-able

Use "Stanford-style" theming to enable you to put your own embargo
notice up.
missing themed embargo page fails safely to unthemed
updated pdf viewer
i18n: Fix the chinese name of chinese language

The current version of chinese language's chinese name is not political neutral.
In fact, which form of chinese (traditional or simplified) can be called "正體"(in traditional chinese) or "正体"(in simplified chinese) is not globally defined.
So, I change the name according to the word used by Microsoft Windows, which is more neutral.
Convert CAPA inputtype statuses from strings to objects, in order to
simplify css class management and internationalization of status strings
(potentially) displayed to the user.
Changed str->unicode in common/djangoapps/utils/.

LMS-2436
Some more str->unicode fixes in instructor and courseware apps.

LMS-2429
Revert to older version of TinyMCE.

We had trouble with Cloudfront/hashed files and need more time
to investigate.
This reverts commit e8f53ac9dc6d8a1d9928787635c7c5f7e409a9ec.
Merge pull request #3067 from edx/christina/revert_tinymce

Revert to older version of TinyMCE.
Merge pull request #3070 from edx/adam/middleware

wiki middleware fix (LMS-2461)
Concept added to Studio advanced components
Skip collectstatic when falling through from rake assets:coffee
Update course_about.html

if course title use Chinese or other language got the 500 error when visit the course_about page ,and the log shows :UnicodeEncodeError: 'ascii' codec can't encode characters in position 0-3: ordinal not in range(128)
Merge pull request #3082 from edx/db/rake-coffee-to-paver-skip-collect

Skip collectstatic when falling through from rake assets:coffee
Update testing.md file.

How to run Python tests for stub servers.
Merge branch 'release'
Fix failing tender.
Merge pull request #3092 from edx/valera/fix_tender

Fix failing tender.
Update doc string for YouTube stub server.

Included information on how to launch the server
on its own.
EOF
Add an option to prevent multiple logins of the same user.