reposconf.py: Creates ConfigHandler class

A class which adds support for repos.conf portage configurations
is being added.
makeconf.py: changes name to ConfigHandler, adds update() stub

For compatibility with RepoConfManager, the MakeConf class has been
renamed to ConfigHandler as well as adding an update() function as
a stub for when RepoConfManager calls it. Changes have also been made
to the error output, to allow for later translations.
config.py: Adds auto_sync, conf_type, and require_repoconfig

Three new options have been added to give users repo config
configurability.
repoconfmanager.py: Creates RepoConfManager class

This class will provide a wrapper for all config types and will
also allow for custom config plugins as well.
db.py: Incorporates RepoConfManager class