feat(engine/bpmn): add signal end event
- related to CAM-110
feat(engine/bpmn): Add call activity configuration for passing business key and all process variables.

related to CAM-1086

chore(ns): Change activiti namespace to camunda
Merge pull request #10 from polenz/CAM-110-SignalEndEvent

Add signal end event
chore(engine): mention task due date

related to CAM-889
updt(migration-guide): update to alpha9 changes

Related to: #CAM-993
chore(actInstId): Add actInsId to task query

related to CAM-1070
Merge branch 'master' of github.com:camunda/docs.camunda.org
add(migration-guide): add hint which @Named() to use
fix(migration-guide): fix linebreak
fix(namespace): revert xml namespace change

- The namespace was changed to http://camunda.org/bpmn in the last
release.
  This introduces a regression as changing the namespace breaks both the
  camunda modeler and the engine.

- For reasons of backwards compatibility, the namespace must not be
changed.

- Reverted to old namespace http://activity.org/bpmn

Related to CAM-1148