Refactored all entity classes: added an interface for each entity, such that alternative data stores can swap out the entity objects with more fitting ones (eg with annotations like Neo4j, JPA, etc or other mechanisms. Internally, only the entity interface is used)

Removing ReadonlyProcessDefinition interface. PVM heritage + all methods were already in ProcessDefinition.

Initializing fields to 0, null, or false is not needed and just duplicates work.

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

Fixing QA and database quirks when handling null values in unique constraint in the context of multi tenancy.

Act-1691: programmatic update of process definition category + fixed to ScriptTaskListener on recent jdk's

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

history reporting done from withing the engine

ACT-1202: Tackled the problem which strangely did not fail on local H2, history entry is created in ProcessDefinitionEntity as well

Added pool and lanes parsing and rendering on diagram + added missing "drop" statements for new indexes added

ACT-655, ACT-661, ACT-667: Clarified form exception, Exposed Process documentation, diagram cutoff bug