Merge branch 'ps/history'

"git history" history rewriting UI. * ps/history: builtin/history: implement "reword" subcommand builtin: add new "history" command wt-status: provide function to expose status for trees replay: support updating detached HEAD replay: support empty commit ranges replay: small set of cleanups builtin/replay: move core logic into "libgit.a" builtin/replay: extract core logic to replay revisions