Make it possible to submit a new external job per CLI

With this command external job submission is possible per CLI.
Per pipe gzipped log file can be transported. No wrapper scripts are needed
it can be easily done from the command line:

 cat log.gz | ssh jenkins set-external-build-result --job b --result 0 --log -
Merge pull request #5 from davido/master

Make it possible to submit a new external job per CLI