make all instances attr read writers

unfortunately the writers have to have self.var =
otherwise it is just a local var
Also need to make the type explicit for all
Protocol included memory_length on the class for now

lib/parfait/vool_method.rb

@@ -12,10 +12,13 @@ module Parfait
   #
   class VoolMethod < Object
 
-    attr_reader :name , :args_type , :frame_type , :source
+    attr :type, :name , :args_type , :frame_type , :source
 
     def initialize(name , args_type , frame_type , source )
-      @name , @args_type , @frame_type , @source = name , args_type, frame_type , source
+      self.name = name
+      self.args_type = args_type
+      self.frame_type = frame_type
+      self.source = source
       raise "Name must be symbol" unless name.is_a?(Symbol)
       raise "args_type must be type" unless args_type.is_a?(Parfait::Type)
       raise "frame_type must be type" unless frame_type.is_a?(Parfait::Type)
@@ -25,7 +28,7 @@ module Parfait
 
     def create_callable_method( type )
       raise "create_method #{type.inspect} is not a Type" unless type.is_a? Parfait::Type
-      type.create_method( @name , @args_type , @frame_type)
+      type.create_method( name , args_type , frame_type)
     end
 
     def compiler_for(self_type)