rename singleton_class to single_class and misc

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

test/vool/test_class_method_expression.rb

@@ -0,0 +1,39 @@
+require_relative "helper"
+
+module Vool
+  class TestClassMethodExpression < MiniTest::Test
+    include VoolCompile
+
+    def class_code
+      "class Space;def self.meth;return 1 ; end;end"
+    end
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      ruby_tree = Ruby::RubyCompiler.compile( class_code )
+      @clazz = ruby_tree.to_vool
+    end
+    def method
+      @clazz.body.first
+    end
+    def test_setup
+      assert_equal ClassExpression , @clazz.class
+      assert_equal Statements , @clazz.body.class
+      assert_equal ClassMethodExpression , method.class
+    end
+    def test_fail
+      assert_raises{ method.to_parfait }
+    end
+    def test_method
+      clazz = @clazz.to_parfait
+      assert_equal Parfait::Class , clazz.class
+      meth = method.to_parfait(clazz)
+      assert_equal Parfait::VoolMethod , meth.class
+      assert_equal :meth , meth.name
+    end
+    def test_is_class_method
+      clazz = @clazz.to_parfait
+      m = clazz.single_class.get_instance_method(:meth)
+      assert m , "no method :meth"
+    end
+  end
+end