CustomConstructor -> CustomClass, which calls specialClass

specialClass is an analog of functools.partial but for classes.
We can now use it instead of partial() in mn, so that Mininet
can introspect on the actual base class.

Fixes #488

bin/mn

@@ -33,7 +33,7 @@ from mininet.nodelib import LinuxBridge
 from mininet.link import Link, TCLink, OVSLink
 from mininet.topo import SingleSwitchTopo, LinearTopo, SingleSwitchReversedTopo
 from mininet.topolib import TreeTopo, TorusTopo
-from mininet.util import customConstructor, splitArgs
+from mininet.util import customClass, specialClass, splitArgs
 from mininet.util import buildTopo
 
 from functools import partial
@@ -69,8 +69,8 @@ SWITCHES = { 'user': UserSwitch,
 
 HOSTDEF = 'proc'
 HOSTS = { 'proc': Host,
-          'rt': partial( CPULimitedHost, sched='rt' ),
-          'cfs': partial( CPULimitedHost, sched='cfs' ) }
+          'rt': specialClass( CPULimitedHost, defaults=dict( sched='rt' ) ),
+          'cfs': specialClass( CPULimitedHost, defaults=dict( sched='cfs' ) ) }
 
 CONTROLLERDEF = 'default'
 CONTROLLERS = { 'ref': Controller,
@@ -311,10 +311,10 @@ class MininetRunner( object ):
                                      self.options.switch )
 
         topo = buildTopo( TOPOS, self.options.topo )
-        switch = customConstructor( SWITCHES, self.options.switch )
-        host = customConstructor( HOSTS, self.options.host )
-        controller = customConstructor( CONTROLLERS, self.options.controller )
-        link = customConstructor( LINKS, self.options.link )
+        switch = customClass( SWITCHES, self.options.switch )
+        host = customClass( HOSTS, self.options.host )
+        controller = customClass( CONTROLLERS, self.options.controller )
+        link = customClass( LINKS, self.options.link )
 
         if self.validate:
             self.validate( self.options )