CFY-783 added force parameter to execution cancel command
CFY-783 merge commit
CFY-817 add execution get api to cli
CFY-783 added doc for 'force' param in cancel execution in CLI
Merge pull request #29 from cloudify-cosmo/feature/CFY-783-add-support-for-cancel-execution

Feature/cfy 783 add support for cancel execution
Merge branch 'develop' into feature/CFY-799-task-retries