Lookup plugins 'sequence' and 'template' now import 'ansible.utils'
appropriately in order to use the 'listify_lookup_plugin_terms'
function.

Also, 'dnstxt' and 'env' now check to see if 'terms' is a string;
without this calls like '{{ lookup('env', 'HOME') }}' fail.

Make more lookup plugins tolerant of new variable system, with a little better 'do what I mean' logic to resolving
what happens if you get a string back as a template result.

Lookup plugins should accept a string or a list, and always return
a list, even if it is just one item.

remove support for multiple vars

This allows using with_fileglob in play context, e.g.
- include: $item
  with_fileglob: tasks/*.yml
as well as prepares for other data to be passed.

implement lookup plugins for arbitrary enumeration over arbitrary things.   See the mailing list for some cool examples.

changelogs yet since this isn't released yet (but 0.3 is)

Also make pep8 show all messages rather than just 1 per code.

constants file so as to not repeat constants between CLI and lib.