2.0.x release

Macro-PR introducing all changes required for 2.0.x

### TODOs

 - [x] remove manual proxying and use proxy-manager instead #20 
 - [x] remove view helper config specific module method #21
 - [x] ~~fix rendering in ZendDeveloperTools' toolbar~~ (moved to #23)
 - [x] provide better service locator names in the YUML diagram
 - [x] ~~provide better service names in the YUML diagram - eventually display aliases~~ (moved to #24)
 - [x] link services from different locators in the YUML diagram
 - [x] ~~discover links between services implementing `Zend\ServiceManager\ServiceLocatorAwareInterface`~~ (moved to #25)
 - [x] ~~discover factories (if possible) that generated the services being shown in the YUML diagram~~ (moved to #26)
 - [x] bump dependency to ProxyManager to `0.5.*` once Ocramius/ProxyManager#83 is completed