revlogdag: add linearize function
See the docstring for a detailed explanation. The linearizer was originally
written by Benoit Boissinot.
subrepo: respect non-default path for incoming/outgoing
Push and pull set repo._subtoppath before pushing or pulling subrepos.
The incoming and outgoing commands needed to do the same.
annotate: fix alignment of columns in front of line numbers (
issue2807)