disable buttons for large courses on legacy and beta instr dash

set max enrollment for downloads to 200
Implemented bulk email interface for new dashboard

Responses to Adam's comments; reset common.py, i18n compliance, deleted extraneous email.html file, fixed an HttpResponse, deleted unnecessary commented-out code, some small style tweaks
Changed GET to POST and xmodule HTML editor call, section CSS
Added acceptance tests for bulk email (through beta dashboard)
Merged in email confirmation modal
API tests, email tests, working notifications
added self to authors style, changed GET to POST
Legacy email tests, removed duplicate code, updated comments, fixed CSS
Revert "Merge pull request #1240 from edx/dhm/config_separation"

This reverts commit ec01253e30a9949223df5e70ffcb4d47f8370556, reversing
changes made to ae8c9710e5a250b1acd083520f8e01b5e46dd5d0.
source-edit.html depends on leanModal
Merge pull request #1156 from edx/feature/cdodge/add-preview-configs-via-middleware

add some middleware to determine whether draft modulestore or non-draft ...
Merge pull request #1305 from edx/jarv/revert-1240

Revert "Merge pull request #1240 from edx/dhm/config_separation"
Removed email acceptance test
Improve accessibility of forums flagging feature

The "Report Misuse" div is now focusable, responds to keyboard input,
and has appropriate attributes to indicate that it is a toggle button.
This fixes FOR-201 and FOR-209.
Increase color contrast for forum features

The icons and text for pinning and flagging ("Report Misuse") had
contrast ratios that did not meet the minimum WCAG requirement of 4.5.
This fixes FOR-200.
Make forums endpoints return better status codes

Previously, AJAX calls would return 400, and page views and attempts
to load inline discussions would return 404 if communication with the
comments service failed. Now such problems cause a 500 status code.
Merge pull request #1215 from edx/flowerhack/feature/bulkemailnewdash_testingcoverage

Flowerhack/feature/bulkemailnewdash testingcoverage
Merge pull request #1303 from edx/db/source-edit-leanModal

source-edit.html depends on leanModal
Ensure that jQuery loads before any other JS dependency
Merge pull request #1265 from edx/gprice/forum-flag-a11y

Improve accessibility of forums flagging feature