CFY-203 added delete deployment command
Update README.md

added docs for delete deployment command
CFY-203 improved a unit test
Merge remote-tracking branch 'origin/feature/CFY-203-add-delete-deployment-REST-API' into feature/CFY-203-add-delete-deployment-REST-API
Merge pull request #15 from cloudify-cosmo/feature/CFY-203-add-delete-deployment-REST-API

Feature/cfy 203 add delete deployment rest api