APY-114: Update Superdesk plugins for distribution-manager

updated __init__ files, moved language plugin to core plugins
APY-114: Update Superdesk plugins for distribution-manager
APY-47: Refactor CDM to include content metadata and make it extensible

updated plugins information, fixed dependencies
removed getTimestamp usage due to CDM metadata modifications
APY-114: Update Superdesk plugins for distribution-manager

information updated and published plugins to pypi
media-archive plugin updated to not use getTimestamp
Merge pull request #503 from cristidomsa/apy-8-implement-x-filter

APY-114: Refactor CDM to include content metadata and make it extensible
Removed accidental cyclic inheritance from acl configuration file
Work on APY-99 Integrate the UI with the refactored REST API
Work on APY-117 Migrate live blog screen to the new REST API
APY-120 : Add support for mongoengine

Sample content item with mongoengine.
APY-120 : Add support for mongoengine

Added validation and also more item samples
APY-121 : Polymorphic support for models

Small updates for polymorphic testing.
some cleanup
APY-112: Make authentication user name case insensitive

converted to lowercase before comparing
APY-47: Refactor CDM to include content metadata and make it extensible

added metadata for publishing images
cleanup
APY-112: Make authentication user name case insensitive

added str.lower instead of sqlalchemy lower func (review comments)
Merge pull request #526 from cristidomsa/auth

APY-47: Refactor CDM, APY-112: Make authentication user name case insensitive
Merge pull request #525 from mihaigociu/apy-8-implement-x-filter

Integrate UI with the refactored REST API
APY-108 : Create content structure for news and package items
Updated Babel library to version 1.3