Add ownership when starting a story

Previously, when a story was started ownership was not assigned.  This
resulted in unowned stories in the sprint.  This change now assigns
ownership of a story when it is started, extracting the value from the
Git configuration's user.name value.
Merge branch 'start-with-ownership'
Pull during trival merge

Previously, there was a complex comparison of the remote tip, local
tip, and common ancestor when determining a trial merge.  This change
simply forces a pull of the root branch before figuring out the root
tip and common ancestor for comparison.

[Finishes #6]
Merge branch 'pull-during-trival-merge'