builddeb: create source archive for ubuntu

builddeb: ignore vcs and build results This one is a no-brainer. Previously, if you tried to build a deb on ubuntu, it would try to diff files in the .hg store. These flags prevent that.

builddeb: copy over .gz and .dsc files We were forgetting to copy over the signature (if it exists) and the zipped diff, so let's do that.

builddeb: ignore errors about find not finding files The debuild command may output less files than we explicitly list so let's not error out if none exist.

builddeb: use the os codename instead of 'unstable' This fixes a lintian error (and indeed, launchpad rejects it) by using the distribution's codename (e.g. xenial, trusty, etc).

builddeb: use sed -i Notice that there is no space after '-i'. This makes it work on both GNU and BSD versions of sed.

dockerdeb: redirect 'cd' in export command to /dev/null This had the unfortunate side effect of causing the environment to have a newline due to the fact that some 'cd' outputs the result of the directory change. So, let's just redirect the meaningless output.

help: avoid using "$n" parameter in revsetalias example Because parsing "$n" requires a crafted tokenizer, it exists only for backward compatibility (as documented in revset._tokenizealias.) This patch updates the examples so that users are encouraged to use symbolic names instead of "$n"s. I'm going to implement alias expansion in templater, which won't support "$n" parameters to make my life easier. Templater is more complicated than revset because tokenizer and parser call each other.

debian: add missing netbase dependency Apparently, some machines don't have this service (launchpad builders are one such example). This adds the correct dependency for test-serve.t.

debian: add missing zip/unzip dependencies