simplify internal plugin dispatching code, rename parts of the py._com plugin helpers

--HG--
branch : 1.0.x

py/execnet/gateway.py

@@ -88,8 +88,8 @@ class Gateway(object):
         self._channelfactory = ChannelFactory(self, _startcount)
         self._cleanup.register(self) 
         if _startcount == 1: # only import 'py' on the "client" side 
-            from py._com import Hooks 
-            self.hook = Hooks(ExecnetAPI)
+            import py
+            self.hook = py._com.HookRelay(ExecnetAPI, py._com.comregistry)
         else:
             self.hook = ExecnetAPI()
 

py/execnet/gwmanage.py

@@ -21,7 +21,8 @@ class GatewayManager:
             if not spec.chdir and not spec.popen:
                 spec.chdir = defaultchdir
             self.specs.append(spec)
-        self.hook = py._com.Hooks(py.execnet._HookSpecs)
+        self.hook = py._com.HookRelay(
+            py.execnet._HookSpecs, py._com.comregistry)
 
     def makegateways(self):
         assert not self.gateways