Commit Briefs
don't include the common commit in log-outgoing (github/master)
log-outgoing used to include also the latest commit in REMOTE-LOCATION, and it's misleading (i.e. vc-log-outgoing on a sync'd repository would still list a commit). This fixes it by calling next-revision on the remote-location, which is nil when we're in sync with upstream.
chores
mostly to avoid long lines (>= 80)
reword docstring to avoid checkdoc complain
checkdoc complained that `uses' should be in imperative form...
rework the vc-dir handling and remove the ugly hack
With this our *vc-dir* looks more like the others. Instead of showing something like stage:edit we only add `M', `D' or `A' (the got status flags), and so we don't need the ugly hack too.