repoman/main.py: Break out a new ebuild check, ThirdPartyMirrors

Consolodate the code from 2 locations into one class.
repoman/main.py: Create ebuild.py and Ebuild class

This moves all relavent data to a class for a common access point.
It also adds an untracked function.
repoman/main.py: Create checks/ebuilds/manifests.py and Manifests class

This moves manifest checks and creation to it's own class
repoman/main.py: Rename x variable in loop to xpkg

This will help clarify what it is better.
repoman/main.py: Replace y with y_ebuild in the loop

This too helps clarify what it is.
repoman/main.py: Split out vcsstatus.py with VCSStatus class

This class scans the vcs to determine ebuilds not added.