Implemented logic to generate field-level access permissions
Implemented field-level permission check of user permissions on document update.
Added method to remove fields for which the user does not have read access before sending response. Said method is used in baseController.show
Changed structure of field-level permissions such that each field has a read and update permission
Added a base permission for reading lists of content (separate from 'read' permission)
Preventing possible NPE in ascertainUserPermissions. Updated some error messages to be more accurate/descriptive.
Added method to build a mongo select statement based on fields that user has permission to view. Using said method in baseController.all
Refactored update function - moved functionality to separate method.