LB-368 : Chained blogs - plugin
Made fix for inserting source with provider.
Made source chained
Merge branch '350-chain-blogs' of git://github.com/sourcefabric/Superdesk into 350-chain-blogs

Conflicts:
	plugins/livedesk/livedesk/api/blog.py
	plugins/livedesk/livedesk/impl/blog.py
	plugins/livedesk/livedesk/meta/blog.py
Refactor manage feeds to use Backbone.