notify: turned a set-like dict into a real set

revlog: let nodestotag be a set instead of a list

replace set-like dictionaries with real sets Many of the dictionaries created by dict.fromkeys were emulating sets. These can now be replaced with real sets.

util: use built-in set instead of util.unique

util: use built-in set and frozenset This drops Python 2.3 compatibility.

Merge with crew-stable

convert/bzr: fix symlink handling (issue1626)

win32text: be more careful about rejecting violating changesets We now try to walk changesets in reverse order from newest to oldest, so that if we see a file multiple times, we treat the newest version as canonical. This should prevent us from rejecting a changegroup that contains an unacceptable commit followed later by a commit that fixes the problem.