rename singleton_class to single_class and misc

was clashing with real ruby method name
also many superclass mismatch fixes
some misc

test/vool/class_send/test_class_def.rb

@@ -19,7 +19,7 @@ module Vool
     end
 
     def setup
-      source = "class Integer;def +(other);X.int_operator(:+);end;end;" + class_main
+      source = "class Integer<Data4;def +(other);X.int_operator(:+);end;end;" + class_main
       ret = RubyX::RubyXCompiler.new(RubyX.default_test_options).ruby_to_mom(source)
       @ins = ret.compilers.find{|c|c.callable.name==:main}.mom_instructions.next
     end

test/vool/class_send/test_class_instance.rb

@@ -27,7 +27,7 @@ module Vool
     def test_class_inst
       space_class = Parfait.object_space.get_class
       assert_equal :Space , space_class.name
-      names = space_class.singleton_class.instance_type.names
+      names = space_class.single_class.instance_type.names
       assert names.index_of(:inst) , names
     end
     def test_compiler

test/vool/class_send/test_class_send_inherited.rb

@@ -7,7 +7,7 @@ module Vool
 
     def class_main
       <<-eos
-        class Object
+        class Space
           def self.one_plus()
             return 1 + 1
           end