Provide base_module to clone_config templates
    
    When cloning from a namespaced repository, the clone_config template may
    wish to use the module with and without the namespace prefix.  Use the
    get_base_module() function to extract base_module and expand it when
    found in a clone_config template.
    
    Resolves: #326
    Signed-off-by: Todd Zullinger <tmz@pobox.com>