bookmarks: rewrite comparing bookmarks in commands.summary() by compare()
This patch adds utility function "summary()", to replace comparing
bookmarks in "commands.summary()". This replacement finishes
centralizing the logic to compare bookmarks into "bookmarks.compare()".
This patch also adds test to check summary output with
incoming/outgoing bookmarks, because "hg summary --remote" is not
tested yet on the repository with incoming/outgoing bookmarks.
This test uses "(glob)" to ignore summary about incoming/outgoing
changesets.
% creating repo
% add and commit
C test.py
% change
M test.py