Low-level class for managing request endpoints
    
    An Endpoint is different from a Page in that it doesn't have menus,
    templates, transactions, etc. It is only defines a URL that can be
    mounted.
    
    https://fedorahosted.org/ipsilon/ticket/38
    
    Signed-off-by: Rob Crittenden <rcritten@redhat.com>
    Reviewed-by: Simo Sorce <simo@redhat.com>