Remove the vendored ibisclient, preferring to use the upstream PyPI one.

group id if it had leading zeroes. Removed the conversion of the id
to an int when passing to get_or_create_group_by_groupid(). Unnecessary
as the id was already validated with a regex.

To render properly on PyPI the long description needs to have its
content type set.

The setuptools version of setup() has some features which make it work
better with the modern pip ecosystem.

bugfix: "single select" control not initialising (introduced single_user on ucamlookup_users.html to initialise "single select")