dirstate.statwalk: explicitly test for ignored directories
This removes a hack where we appended '/' to a dirname so that:
- it would not appear on the "dc" dict
- it would always be matched by the match function
This was a contorted way of checking if the directory was matched by
some hgignore pattern, and it would still fail with some uses of
--include/--exclude patterns.
Things would still work fine if we removed the check altogether and
just appended things to "work" directly, but then we would end up
walking ignored directories too, which could be quite a bit of work.
This allows further simplification of the match function returned by
util._matcher, and fixes walking the working directory with a
--include pattern that matches only the end of a name.
util._matcher: unify pattern normalization
This should fix
issue347.
It also highlights one issue with the directory walking code when
you have an --include pattern that matches the end of a filename.
This is fixed by the next patch.