Implemented sbt build step for DSL.
Removed default value for required argument
Added tests for minimal and full call to sbt method
Reordered parameters according to expected most frequent usage
Merge pull request #58 from jabbrwcky/JENKINS-18334

Implemented sbt build step for DSL.
JENKINS-18396
- Add ability to inject helper classes into GroovyClassLoader used to
  execute DSL code.
Merge pull request #60 from oesolutions/18396

JENKINS-18396
Fixing TopLevelHelper tests.
Merge pull request #61 from oesolutions/master

The tests for the TopLevelHelper are broken.
Add smaller git method signatures.
Allow an empty list of recipients.
Fix sendToRequester, made test to check.