Added support for using "an" to specify a role name that begins with a vowel.

e.g. an administrator instead of a administrator
Added extra roles to support testing of an syntax
Added support for

Then I should see the list of <list name> containing
and
Then <role> should see the list of <list name> containing
Merge pull request #12 from MikeHanson/master

Add support for "an" when specifying a role