Hierarchical configuration files for PyBugz. Commits for support this
functionality follows this one.
TODO: The 'default' functionality is out. It will be solved by inheriting.
* bugzrc.example: This is now example of user's config file.
* conf/conf.d/gentoo.conf: Gentoo configuration file.
* conf/conf.d/redhat.conf: Config for Red Hat's bugzilla.
* conf/pybugz.conf: System configuration.
* man/bugz.1: Mention where to look for configuration documentation.
* setup.py: Not sure if this is OK, but try to install configurations.