hgext3rd/__init__.py

tag: disallow tagging the working directory

It's kinda silly, but a clear error message is better than a stacktrace about
subscripting `None` when trying to generate the default commit message.  I'm
surprised that `.revsingle(..).node()` returns None instead of `nodemod.wdirid`,
but now there's a test to catch if this changes.

# name space package to host third party extensions
import pkgutil

__path__ = pkgutil.extend_path(__path__, __name__)