Display help summaries for checklists

[jkakar]

It would be nice to do make the first line in a checklist markdown file be a short description. List this sentence beside the checklist name when check list is run. It would make it easier to have terse checklist names while still being able to describe what it's purpose is. For example, we might have a checklist called credit with a description like Apply a credit to a user's account. When you run check list it could display something like:

# Checklists
project
  credit  Apply a credit to a user's account
  thing   Do something else

And so on.

[csquared]

I love this idea. Already implemented it in the JS List Parser -- will backport to ruby for the command line.