contrib: make import checker always think in terms of bytes The doctests now do some regrettable things, but they'll always work since we're dealing with ASCII module names etc.

contrib: work around some modules not existing on Py3 in import checker

tests: stop using old except syntax in test-bundle2-format

tests: update test-archive to always use hashlib We don't need the fallback to the old modules anymore.

md5sum: assume hashlib exists now that we're 2.7 only

undumprevlog: update to valid Python 3 syntax I didn't do anything to ensure correctness here, just enough to avoid tracebacks in the import checker, which uses the native ast module to try and parse all our Python files.