fixed bug when single value filter is applied in users api

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

switch to APIView to support url conventions

merged with master

add pagination to /api/users

add support of id based filtering

add num_pages field to users api output

add tests for paging data and ability to parse page_size from request

using ListAPIView and DRF filters

Disallow unfiltered lists

Updated docstrings

cdodge/get-ip-restriction-list-from-config: change settings name to make clearer and make sure we are getting values from lms.envs.json

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