Previously, all FunctionBrokers used the same global set of type marshalers to handle IPC. The marshaling behavior is endpoint-dependent so it is done with the EndpointHandler. This patch makes the EndpointHandler used by a specific RPC function into a template parameter to the function's FunctionBroker. It also divides up the current special type handling into two cases -- FileDlgEndpointHandler for plugin file dialog brokering, and SslEndpointHandler for SSL communication brokering.
The FunctionBroker is a special kind of FunctionHook that brokers the hooked function on another process. In the child process, it uses the FunctionBrokerChild to request that the FunctionBrokerParent run a function and return the response. It handles most cases of parameter, return value and error marshaling on its own. It also guarantees that requests are issued from the proper thread.
