fix(engine) CAM-2124 add update incident to mybatis configuration
fix(async/startEvent): fix behavior on async start events

This commit fixes two issues:

- The variables will be written in history during the start of a process with an async
  start event.
- The right start event will be executed during the start of a process
  with multiple async start event.

related to CAM-2492, CAM-2520

Conflicts:

	engine/src/main/java/org/camunda/bpm/engine/impl/persistence/entity/ExecutionEntity.java
	engine/src/main/java/org/camunda/bpm/engine/impl/pvm/runtime/AtomicOperationProcessStart.java
	engine/src/test/java/org/camunda/bpm/engine/test/bpmn/async/AsyncStartEventTest.java
make it run
adaptation of CAM-2492 to our camunda-engine
Merge branch 'tifspp1089'
[maven-release-plugin] prepare release 7.0.0-unitedinternet-7