debugdag: stop wrongly sorting parents The dag being dumped is not in a format that allows us to reconstruct the original dag as the parent revisions are normalised.

obsolete: avoid slow, generic date parsing Simple profiling of `hg log -r .` revealed ~18,000 calls to mercurial.i18n.gettext() on the author's repository. The culprit was 3 _() calls in util.parsedate() multiplied by ~6000 obsmarkers originating from the parsing of obsmarkers. Changing the obsmarker code to parse the stored format of dates instead of going through a generic path eliminates these gettext() lookups and makes `hg log -r .` execute ~10% faster on the author's repo. The performance gain is proportional to the number of obsmarkers. The author attempted to patch util.parsedate() to avoid the gettext() lookups. However, that code is whacky and the author is jet lagged, so the approach was not attempted.

build: don't use -s flag for `which` `which -s` is a BSDism that doesn't exist on other versions of `which`. That means that even on Mac OS X, `make osx` breaks if you have another utils package installed (e.g. debianutils installed thru fink). Redirect output to /dev/null instead.

contrib: drop obsolete sample.hgrc This was full of bad suggestions and is obsoleted by hg config --edit.