parameters for Given/When/Then/etc

[ToadJamb]

I thought it would be nice to be able to do things like:

Given 'a user named', 'John'
When 'I enter a password', 'password for John'

It turns out this is really easy. I already have it working in this commit.

For my current purposes, I don't care that this is tested and such, but if the owner is interested in pulling this functionality in and does care to have it tested, I would be willing to consider doing that work.