Fix offline_gradecalc

Bug: Throws error when can't find a user on the request object for grading or can't find a session attribute.

Fix: Added a user attribute with a value of the current student and a session attribute with a value of an empty dictionary.
fix crash in peer eval xmodule

As documented in Jira LMS-806:

Steps to reproduce:
* as one user, for a peer evaluated problem, enter something that needs
  peer grading
* as another user, log in and fire up the peer grading panel. You should
  see something that needs attention, a yellow exclamation badge
* clicking on the "do grading" panel will fail with a 500, stacktrace
  attached.
* it's possible that the question where this is being done must first have
  professor calibration done in order for peers to be able to actually get
  work to grade.

Don Mitchell debugged this with me and saw some problems in the ways
that the peer_evaluation xmodule code was accessing dates. Instead of
using the normal lms accessors, by going straight into the _module_data
it would be bypassing some important code (caching?). Fixing this to be
more standard did the trick.
add a metadata cache and re-compute ignore when deleting a course to speed up the whole thing as well as squelching warnings in the console output
add same optimizations to the clone course command
rename clone.py to a more descriptive clone_course.py
show the organization, course number, course run in the course listing page in CMS
one field had wrong label nesting
Bump up pip requirement to latest.

    Solves an issue with using git > 1.8.1 for github based pip requirements.
Integrate JsonResponse into lms/djangoapps/instructor/views/api.py
Translate messages early
Auto-enroll course staff to fix "View Live".

STUD-554

Code review feedback.
tie in the normal courseware link url rewriting in capa module since that presents HTML via an Ajax callbacks and not via module_render.py
Studio: revises markup and visual styling for course listings metadata
Add unit tests to exercise common_exceptions_400 decorator
Add helper methods to hide internals of how users are enrolled in courses.

Remove _

Minor cleanup.
fix broken test due to HTML change
template fixes on instructor dash
Merge pull request #570 from edx/fix/cdodge/add-metadata-caching-to-delete-course

Performance enhancements for django-admin commands to delete and clone course
tz fix in openendedchild
Small fixup to final print statement in Create Dev Env script

Fixed Typo