List Jobs recursively in hudson.cli.ListJobsCommand

Currently, `list-jobs` simply lists all jobs associated with particular view. I propose to traverse all subviews that might be associated. This situation occurs when `View` implements `ViewGroup` as well.

This change is apparent when Nested View Plugin is used. A top level view appears empty prior this change while after this change it lists all the jobs transitively contained in the view.

Reworked #787.