Setup ControllerLoader consistently
Setup ControllerLoader consistently

- Changes the config key for controllers from 'controller' to
  'controllers' and the sub-key 'classes' to 'invokables'.
- This commit removes support for DI, but it will be added back in a
  later commit.
- Small cleanup to ServiceManager's circular dep checking.

weierophinney/zend-modulemanager,Xerkus/zend-modulemanager,MadCat34/zend-modulemanager,zendframework/zend-modulemanager