testing fetching a commit compare via github for full diff info
wip, comment line calc seem right now, needs lots of cleanup
cleanup, mostly working now
refactor, add PullRequest and PullRequestList classes

add user cfg for user/pass for basic auth
fix usage of 'github-comments repo_owner repo_name prnumber
convert to optparse, add ability to show pull request comments

We could show pull request review comments before (aka, comments
on diff's), now we also show the general comments.
update readme