Merged BpmnDeployer refactoring. Made classnames and class members consistent with typical Activiti conventions. Renamed ExpandedDeployment to ParsedDeployment and extracted Builder and BuilderFactory into its own classes.

Merge branch 'activiti6-bpmn-deployer-refactoring' of https://github.com/stpm/Activiti into stpm-activiti6-bpmn-deployer-refactoring

Ported https://github.com/Activiti/Activiti/commit/bae3f8feb99a0b2f105f3837fa764b6637e530e8  to v6 + added the custom maybatis mappers from v5

Multi instance refactoring: upgrade scripts for IS_MI_ROOT_. Upped the (internal) version to 6.0.0.1.

Multi instance refactoring: introduced the 'IS_MI_ROOT_' column to indicate an execution is the root of a multi instance. Every multi instance (sequential and parallel, parallel already had it) will now spawn an execution that acts as parent for the whole multi instance. This has two benefits: cleanup becomes way easier and it opens up the possibility to dynamically add new instances to a multi instance (not yet implemented).

Porting 'terminateAll' to v6: cherry pick of https://github.com/Activiti/Activiti/commit/a67374d65b93b22590da9e45e149e5433c35408e

Porting 'terminateAll' to v6: cherry pick of https://github.com/Activiti/Activiti/commit/0727dd10c86cbb50089979289e300c6998a159b2

# By Tijs Rademakers
# Via Tijs Rademakers
* 'activiti6' of https://github.com/Activiti/Activiti:
  #710 PR merge to Activiti 6
  Fix history level checking in test
  Fix Activiti 5 compatibility issue due to wrong Context class
  Added dyanmic bpmn support for sequence flow conditions and scripts

utility classes that handle the implementation of much of what
BpmnDeployer does.  This will make it easier to write deployers for
other persistence systems which still do much of what BpmnDeployer
does.  The new classes are:

* BpmnDeploymentUtilities - which handles making deployments and process
  definitions consistent with one another
* CachingAndArtifactsManager - which ensures that all process
  definitions and process definition infos are cached and stored in the
  appropriate places
* EventSubscriptionManager - which handles removing obsolete event
  subscriptions from previous process definitions, and creating new
  subscriptions for new process definitions.
* ExpandedDeployment - which is an intermediate representation of a
  deployment that makes it relatively convenient to get at all of its
  resources and process definitions, and the BPMN models and parses
  related to the process definitions, and to track the relationships
  between them.
* ProcessDefinitionDiagrammer - which encapsulates the creation of a new
  diagram resource
* ResourceNameUtilities - which encapsulates static methods related to
  resource names, including BPMN and diagram resource names.

Fix activiti 6 UI not working on some languages (see https://forums.activiti.org/content/activiti-6-ui-internationalisation-problem)

Implement ClassDelegateFactory and DefaultClassDelegateFactory, and use them in the DefaultActivityBehaviorFactory and the DefaultListenerFactory.

Added accessor methods to ProcessDefinitionQueryImpl and DeploymentQueryImpl.

ACT-4079 (NullPointerException in DbSqlSessionFactory.isBulkInsertable() when Custom Entity is inserted) : fixing Oracle, the old 'get()' needs to be back, but now _after_ the containsKey