Update to work with non-200 jenkins responses

- Jenkins started sending back 201 "creeated" for kicked jobs
- Add a test that it raises the appropriate exception for a 404 response as an
error case.
Merge pull request #11 from mitechie/fix-201-jenkins

- Jenkins started sending back 201 "created" for kicked jobs
- Add a test that it raises the appropriate exception for a 404 response as an
error case.
- Fixes #10