* Moved the --list-hosts option that is common to both `ansible` and
`ansible-playbook` into utils/__init__.py (corrects a FIXME)
* Wrote new help text for the --list-hosts option that makes sense
for both of the commands that it applies to
* Changed the usage argument in `ansible-playbook` so that it is
setup in the base_parser method the same way that it is in
the `ansible` executable
* Updated the help text for several options to correct typos,
clarify meaning, improve readability, or fix grammatical errors.
In the case of `ansible-pull`, I changed the help text so that
it adheres to the same standards as the other executables.