This is the "gather" module.  This module is used to gather packages and their
dependancies from repositories and lay them out in a logistical manner.  A
list of package names should be passed in to find matches in configured repos
and depsolve.  We'll steal lots of code from repotrack.

ROADMAP

a) Use yum.comps to parse our comps file to generate a list of packages to
   depsolve and download. (this is for testing, this will eventually go into
   a higher level module)
b) Wire up something to actually download the package list and write it out
   somewhere.

CONSIDERATIONS

Probably should allow continuing if a package isn't found in a particular arch.
Probably should error if a package isn't found in any arch.

QUESTIONS

Do we createrepo here, once we've gathered our packages?