Making entity manager interfaces consistent: removing duplicate methods (findById/getEntity/..) and make sure they pass the entity cache

Refactoring entity manager usage: making the entity manager instances engine-scoped instead of a Session implementation (ie command scoped).
This way, all the previous Context.getXXX calls can be replaced by direct invocations. Won't influence performance that much, but still nicer from an architectural point of view.

Format back to 2 spaces for now, merging back from Activiti 5 is really an issue with spacing differences

- Introduced AbstractEntityManager as parent class for all EntityManager classes (and removed methods from AbstractManager)
- Introduced new getList method on AbstractEntityManager, that replaces data from the db with data in the cache (which can be more up to date) for correcter results

Refactoring DeploymentCache: introducing DeploymentEntityManager and DeploymentManager. Made DeploymentCache an interface for pluggability