ACT-2020: Improvement in RuntimeService identity link API.
Bugfix according to http://forums.activiti.org/content/how-properly-start-new-process-inside-service-task
Merging in Spring Boot pull req from Josh Long
Merge pull request #280 from wendelkerr/ACT-2020-IdentityLinkRuntime

ACT-2020: Improvement in RuntimeService identity link API.
Merge remote-tracking branch 'remote/master'