Merge pull request #25 from domcleal/readme

Small fixes to the README
Add PR import rake task

Jobs can be queued for all PRs in a given repo using:

  rake import:prs REPO=puppetlabs/puppet

Individual PRs can be queued by using PR=123 in addition.  This also changes
the PR data extract to read the JSON layout used by GitHub for listing PRs, as
well as the normal hook JSON layout.