Livebridge

* Added MongoDB storage driver.
* Added Dummy storage driver.
* Added REST API.
* REST-API is optional. Both LB_WEB_HOST and LB_WEB_PORT have to be set.
* Control data can be updated via REST-API.
* Code cleansing.
* Extended docs for Web API.

* Ability to store control data in database storage.
* Asynchronous loading of control files on s3.
* New configuration env-vars: LB_POLL_CONTROL_INTERVAL, LB_DB_CONTROL_TABLE or LB_DYNAMO_CONTROL_TABLE
* Test coverage 100%
* Code cleansing
* Upgraded Python dependencies
* Updated docs

* Upgraded livebridge dependency
* Added requirements-dev.txt
* Fix for aiohttp session.close()

* Every Liveblog is checked every 10 minutes (default) in the background for status change. (**open/closed**)
* Archived (closed) blogs are not being polled for new postings.
* Added **source_check_interval** to config options.
* Added **verify_ssl** to config options. SSL verification check controllable through config.
* Fixing lb_highlight for Liveblog 3.3+

* added liveblog target, still experimental
* upgrade dependencies