derive binary code form word

long ago hacked the binary code to use integers (thus forsaking correct
arm binaries)
Finally fix by deriving from Word which now has correct binary access
Dumped binary.name in the process, that is available from the method

lib/parfait/method.rb

@@ -23,7 +23,7 @@ module Parfait
       raise "No class #{name}" unless clazz
       self.for_class = clazz
       self.name = name
-      self.binary = BinaryCode.new name
+      self.binary = BinaryCode.new 0
       raise "Wrong type, expect List not #{arguments.class}" unless arguments.is_a? List
       arguments.each do |var|
         raise "Must be variable argument, not #{var}" unless var.is_a? Variable