Reorder logic to make more sense.
Remove debugging print from par.
Pass all params to task.
Small refactoring for maintainability.
Complain and advise if hosts file is not found.

Fixes #3.
Don't try to use passwords for SSH.
First pass at colorizing output.
Revert "Pass all params to task."

This reverts commit d1d08f2bbbbd803200dc446621d47d390ff19453.
Add screenshot to README to demonstrate colours.