Packages09

Wow, what a pain :>  I guess this should actually be re-factored, since there is now a little code duplication, but I think this is a good starting point, pending your review.  Maybe eligible for a devel branch?  Otherwise if you're not fussy, I'm pretty sure this all works.

In short:
1) Scan `.meteor/versions` (if it exists) in addition to only `.meteor/packages`
2) If package is not in `packages` dir, look for it in `~/.meteor/packages/name/version`
3) When scanning a package folder, first check if unipackage.json before parsing package.js.  If it does, add all `prelink` resources for all architecture builds that `use` famono.

Missing?
1) I assume a package exists in the versions file, I'm pretty sure Meteor will throw an error otherwise

Sorry I accidentally diffed it off my other PR.  But maybe that's good if we go that route.