STUD-1312

refactor _generate_items_for_subtask not to chunk queries

use django's iterator methor for querysets

remove bulk email query settings

use read_replica if available, since this is read-only

update changelog

Changes requested in PR

This commit implements STUD-1490, allowing creation of components
on the container page. It also enables the delete and duplicate
buttons now that new content can be created that would benefit.

Note that it also creates shared functionality for adding components,
and refactors the unit page to use it too.

Added new error message that displays when HTML5 video is not supported altogether. Make sure spinner gets hidden when error message is shown. [BLD-638]

LMS-1296

STUD-1562

Set initial video quality to large instead of default to avoid automatic switch to HD when iframe resizes. [BLD 981]

STUD-1562

Features by Jeff Ericson and Nick Parlante squashed
down to one commit.

-shuffle of choices within a choicegroup (Nick)
-answer-pool subsetting within a choicegroup (Jeff)
-masking of choice names within a choicegroup, (Nick)
 used by shuffle and answer-pool
-targeted-feedback within a multiplechoiceresponse (Jeff)
-delay-between-submissions capa feature (Jeff)

player.getAvailableQualityLevels returns a non-empty array, it will eventually display, if HD qualities are available (highres, hd1080, hd720). [BLD-937]

STUD-1306

LTI: Update resource_link_id to change on import to another system or context (BLD-768).

Changed tiny-MCE to not load CSS files dynamically.
Added CSS files for tiny-MCE in env files.
Moved TinyMCE files to directory structure required by Jake command.
Changed clients of "tinymce.min.js" to use "tinymce.full.min.js" instead.
Updated CHANGELOG to indicate tinymce version 4.0.20.
Renamed tinymce.css.
Directions for creating tinymce.full.min.js and commenting of edX changes.
Updated comments related to disabling dynamic JS and CSS file loading in tinymce.
Allow TinyMCE to handle CSS within the iframe.

Detailed commit messages:
deleted old tinymce

new tinymce
js changes to support new tinymce
scss changes for alignments

Include all the controls on the toolbar that we previously had.

Changes to support Bulk e-mail usage.

adding new studio skin for TinyMCE4

Get handling of static image links working again.

Delete old Studio skin.

Version 1.3 of CodeMirror plugin.

Modify paths for location of CodeMirror files.

Fire events when CodeMirror Editor is open and closed.

Needed to switch static links back and forth.

Remove CodeMirror tabbed editor.

fixed tinymce visual editor css

Change how we detect that an image has been inserted.

made the codemirror look more studio-like

reordered the tinymce buttons

Update unit tests.

Update acceptance test for image plugin.

Make sure to strip out temporary caret.

It can get left behind in style blocks.

Test for style block being maintained.

Allow TinyMCE to create p's, else formatting doesn't work.

Add tests for toolbar buttons and converting links.

Add test for code format toolbar button.

Remove unnecessary code.

Remove unused testing templates and unused tabs.

Update tinymce paths.

Fire an event with the link plugin closes so we can rewrite links.

pep8

Updates from code review.

Change the name of the button to "Edit HTML".

Changed menu name for consistency, but we don't show it.

Changed name of "code" toolbar button to "Code block".

Switch from tabbed Visual/HTML Editor for HTML modules to showing the code editor as a plugin within TinyMCE (triggered from toolbar). STUD-1422

Fire events before and after the image dialog is shown.

We use this to rewrite links.

Change the event handling for image plugin.

Fixes FireFox bug, and allows us to correct the image path when we show the plugin (as opposed ot only correcting path when we close the plugin).

Code review feedback.

Fire events before and after the link dialog is shown.

This allows us to convert the static links.

Remove unnecessary helper method.

keeping the component editor inside the component window

Use compressed CodeMirror file.

replaced code icon in TinyMCE editor; simplified UI on TMCE toolbar

Change code editor icon to say HTML.

Move code style block button.

Update tests for minor UI changes.

Code editor button no longer shows an icon, and code style toolbar button location has moved.

Fix typos.

This reverts commit b4ba04ba.

Fix donwload subs for non youtube videos and non-en language - continue.
Add acceptance tests.
Add detetion of assets on request.
Updated docstring.
Add fixes and acceptance tests.
Fix acceptance tests.
Update docsrtings and cleanup code, resful for language_id.
Specify exception type in POST.
Fix url in upload module.
Improve exception handling.
Remove 'en' and catching in editable_metadata.
Move descriptor.get_context test to lms tests.
Add query parameter to translation dispatch.
Response to format parameter of translatin GET request.
Fix Acceprance test: Metadata Editor.
move handlers to proper scores.
Split video player into smaller files.
Add ugettext and fix typoes.
Add changelog.
Support for downloading non-ascii filenames.
Change event binding.
Add content-language to download requests.
Reractor POST handler to not update self.transcripts.

Settings for ENABLE_STUDENT_NOTES and ENABLE_TEXTBOOK in CMS.
Do not display empty collection tabs.
Updated Changelog.

We had trouble with Cloudfront/hashed files and need more time
to investigate.
This reverts commit e8f53ac9dc6d8a1d9928787635c7c5f7e409a9ec.

Switch from tabbed Visual/HTML Editor for HTML modules to showing the code editor as a plugin within TinyMCE (triggered from toolbar). STUD-1422

Changed "Status Page" -> "Page".

UX:
    support for displaying built-in tabs
    restored drag and drop on Studio Pages
    additional styling for fixed state on Studio Pages
    add a new page action added to bottom of Studio Pages

Dev
    changes for viewing tabs in studio,
    refactored the tab code,
    decoupled the code from django layer.
    is_hideable flag on tabs
    get_discussion method is needed to continue to support
external_discussion links for now since used by 6.00x course.
    override the __eq__ operator to support comparing with
dict-type tabs.

Test
    moved test code to common,
    added acceptance test for built-in pages
    added additional unit tests for tabs.
    changed test_split_modulestore test to support serializing objects
that are fields in a Course.

Env:
    updated environment configuration settings so they are
    consistent for both cms and lms.

a page level javascript SR object to enable reading of alert messages.
LMS-2158