Refactoring shell command provider class name.
Merge pull request #165 from EricWittmann/sramp-shell-api-2

Refactoring shell command provider class name.
Fixed an problem where a deriver could not create a relationship from
the source artifact to a derived artifact.  Also added a unit test for
custom derivers.
Merge pull request #166 from EricWittmann/sramp-141-deriver-relationships

(sramp-141) Derivers unable to create relationships from original artifact to derived