Exploratory Support for Twisted-Native Load Balancing

 * develop a twisted.application API that can be used by other applications
   to load balancing
   . a service needs to indicate that it is load balancing
   . if it is, it needs to read its load balancing configuration object
   . it needs to start up one or more proxies
   . it needs shutdown its main service and replace it with a listening service
 * in order for this to happen, most of the responsiblities of the proxy
   manager need to move out into a t.a.service object
   . the following need to be managed: proxies, schedulers, connections, and
     configurations
 * likewise, connection tracking and managerment need to be taken out of the
   scheduler code and put into the service management code
   . schedulers need to have all host data removed from them
   . they need to be passed only one parameter upon initialization: the lb
     algorithm type
   . the proxy should not access the scheduler directly, it should ask the
     proxy manager to do it on its behalf (by calling the appropriate pm
     method)
 * static load balancring service
   . number of proxies are determined by configuration
 * dynamic load balancing service
   . number of proxies are determined by load
   . need to define "load"
 * possibly add proxy mixins/subclasses for different protocols (HTTP, DNS,
   etc.)