rebase: move destination computation in a revset This is the first step toward making the "default destination" logic more clear and unified. The revset is private because I'm happy to delay the bikeshedding until after the clean up happened.

debian: include bash completions in mercurial-common

debian: install hgk as part of mercurial-common (issue4829) Leaving the hgk binary in /usr/bin causes some lintian warnings, and downstream packages poke it in /usr/share/mercurial, so we'll just stash it in there. Rather than patch hgk.py as part of the Mercurial install, just drop a config file in /etc/mercurial/hgrc.d that points to the installed hgk.

debian: install config files as part of mercurial-common Future patches will start putting config files in /etc/mercurial/, this just installs them.

debian: configuration so that cacerts is properly loaded This will be included in the mercurial-common package in a followup patch.

debian: install hg-ssh to /usr/bin just like downstream

highlight: remove temporary hack to overwrite repo.getcwd Now hgweb does it globally.