localrepo: convert _updatebranchcache from nodespace to revspace _updatebranchcache used to use revlog.reachable. After the switch to revlog.ancestors, we can now clean it up a bit and switch the algorithm from nodes to revs.

discovery: convert legacy part of checkheads to revs from nodes After a recent switch from revlog.reachable to revlog.ancestors, clean up this old call site, switching it from nodes to revs.

transplant: convert applied() algorithm from nodes to revs After a recent switch from revlog.reachable to revlog.ancestors, clean up the code a bit to use revs rather than nodes.

revlog: remove reachable and switch call sites to ancestors This change does a trivial conversion of callsites to ancestors. Followon diffs will switch the callsites over to revs.

revlog: add incancestors, a version of ancestors that includes revs listed ancestors() returns the ancestors of revs provided. This func is like that except it also includes the revs themselves in the total set of revs generated.

scmutil: change canonpath to use util.samefile (issue2167) Fixes (on Windows in cmd.exe): $ hg -R v:\x\a status V:\x\a\bar abort: V:\x\a\bar not under root where v:\x\a is a valid repository with a checked-out file "bar" (Note the difference in casing: "v:\" versus "V:\")

win32.py: let samefile and samedevice work on directories too

rebase: do not add second parent to rebased changeset (drop detach option) (BC) Rebase now behaves as if --detach was always passed. Non-merges are rebased as non-merges, regardless of their parent being an ancestor of the destination. Merges will usually be rebased as merges unless both of their parents are ancestors of the destination, or one of their parents is pruned when rebased. This only alters the behavior of rebase when using the --source/--rev options. --detach option is deprecated. All test changes were carefully validated.