Settings service backward compatibility

(cherry picked from commit 83dc3a3)

(cherry picked from commit aa3b9dc)

Switched to rebased XBlock version + restored some xblock dependencies. 

changes to make things work as expected after rebase with master branch
having notifications

Reverted to using non cached permissions check as cached version fails tests (and there are no clean way to make it pass)

Switched to using cached_has_permission in templates, rather than having those permissions in template context

Fixed missing `user` context variable in dicussion course + switched to using more efficient `cached_has_permissions`

Global setting for asynchronous ajax calls - to overcome firefox's strictness about using synchronous ajax with credentials

(cherry picked from commit a7c0a2a)

completed tests and added type filter

removed organizations app

migration to delete tables

Conflicts:
	cms/djangoapps/contentstore/views/helpers.py
	common/static/coffee/src/discussion/content.coffee
	common/static/coffee/src/discussion/discussion_filter.coffee
	common/static/coffee/src/discussion/discussion_module_view.coffee
	common/static/coffee/src/discussion/discussion_router.coffee
	common/static/coffee/src/discussion/views/discussion_content_view.coffee
	common/static/coffee/src/discussion/views/discussion_thread_profile_view.coffee
	common/static/coffee/src/discussion/views/discussion_thread_show_view.coffee
	common/static/coffee/src/discussion/views/discussion_thread_view.coffee
	common/static/coffee/src/discussion/views/new_post_view.coffee
	common/static/coffee/src/discussion/views/response_comment_show_view.coffee
	common/static/coffee/src/discussion/views/thread_response_show_view.coffee
	common/static/coffee/src/discussion/views/thread_response_view.coffee
	lms/djangoapps/django_comment_client/forum/views.py
	lms/static/sass/discussion/_discussion.scss
	lms/templates/discussion/_discussion_module.html
	lms/templates/discussion/_filter_dropdown.html
	lms/templates/discussion/_js_head_dependencies.html
	lms/templates/discussion/_thread_list_template.html
	lms/templates/discussion/_underscore_templates.html
	lms/templates/discussion/index.html
	lms/templates/discussion/mustache/_inline_discussion.mustache
	lms/templates/discussion/mustache/_pagination.mustache
	lms/templates/discussion/mustache/_profile_thread.mustache

Also contains:

* mattdrayer/rebase-20140722b: cherry-pick 0325694
* mattdrayer/rebase-20140722: cherry-pick e8b1217
* Sessions API Documentation
* mattdrayer/rebase-20140722: cherry-pick ofao48d
* mattdrayer/rebase-20140722: cherry-pick b0c343c
* mattdrayer/rebase-20140722: cherry-pick d56e973
* mattdrayer/status-500-fix: Small API bug
* added content_id to workgroup review submissions
* mattdrayer/api-user-preferences-delete: Added new Detail view, GET/DELETE operations
* mattdrayer/rebase-20140722: cherry-pick 0624385
* handle exception if user never accessed any course module
* mattdrayer/rebase-20140722: cherry-pick caada51
* cdodge/add-progress-publish-api-endpoint: expose a new xblock runtime publish special cased event type 'progress' which adds an entry into the CourseCompletions table
* add default setting for feature flag in common.py
* mattdrayer/rebase-20140722: cherry-pick 7a1e12c
* mattdrayer/rebase-20140722: Functional stabilization

asadiqbal08/api-address-based-restriction:API Security: IP address based restriction added MCKIN-1108

uncomment the code

Includes:
* Initial API implementation
* API_KEY header fix
* Fixed indentation error
* move api from common to lms
* Course-Group Relationships
* wip
* add parsing of overview content blob
* initial implementation
* get course updates API method
* get course static tabs API methods
* add unit tests
* fix some merge conflicts and remove some extra print statements picked up in rebase
* better constrain some of the course url regexs to expect a triple for courseId
* add ability to enroll users into courses
* wip
* add queryable group lists
* add a GET endpoint to /api/groups/{groupid}/courses to get the list of courses associated with the group (program)
* return the display names when listing all courses in a group (program)
* create optimized course tree query API endpoint
* make sure group profile data is properly serialized and deserialized. There appears to be a difference between how the Django test client handles things. Disabling unit test for now to unblock UI devs
* null guard
* fix broken unit test
* add GET endpoint to group/user relationships
* Added Security to session api as requested in #785
* Storing passoword history of user and validation for user's email and username
* Moved security tests to lms also
* add two FEATURE flag overrides to enable the security features
* remove unnecessary settings overrides (because they are 'feature flags')
* Adding ratelimiting on login api
* Migrated from Function-Based Views to Class-Based-Views
* Create new Account/Login Audit Log
* The API should provide for an audit log when a user creates a new account or logs into the system.
* UserList.post() now creates UserProfile, UserPreference records
* Group Profile fix
* Filter group subgroups by group type
* Application reorganization
* Name is now required during group creation
* Added null check for profile name
* User must reset password functionality added
* User must reset password dunctionality added
* Added user password reset functionality
* Add password reset api and implemented Password history
* Remove unused imports, password reset message text

Add cohorted_threads_privacy cohort setting: a user that is not in any cohort will only see non-cohorted threads.

Add ENABLE_DISCUSSION_EMAIL_DIGEST feature, to enable discussion emails digest by default for all users