This implements rhpkg part of functionality sent to osbs/atomic-reactor at https://github.com/projectatomic/osbs-client/pull/229 and https://github.com/projectatomic/atomic-reactor/pull/275.
I just added a second commit that also implements a getter for the autorebuild value.
Looks fine with me.
@ausil ?
Related pull request which adds bash autocompletion for this command https://pagure.io/rpkg/pull-request/14