Enhancement: Better performance and simpler logic (somehow).

+ Turned at most everything(most functions returning data) into generators.
+ Created a LiveStatusThread which handle completely a session.
+ LiveStatus_broker.manage_lql_thread():
    > Simplified/Factorized
    > No more busy loop. (a dedicated thread listen for new connections).
+ Misc simplifications.

There are still cleaning to be done but this is a first usable state. 

It only needs shinken master to be updated with following pull request: https://github.com/naparuba/shinken/pull/1348