passing values to macros

conceptually still a bit open, leaving the hack in for now
passing values to the macro instead of sol instances

test/sol/test_macro_expression.rb

@@ -26,12 +26,12 @@ module Sol
       assert_equal SlotMachine::PlusEquals , @ins.class , @ins
     end
     def test_arg1
-      assert_equal  Sol::LocalVariable , @ins.a.class
-      assert_equal  :arg , @ins.a.name
+      assert_equal  Symbol , @ins.a.class
+      assert_equal  :arg , @ins.a
     end
     def test_arg2
-      assert_equal  Sol::IntegerConstant , @ins.b.class
-      assert_equal  1 , @ins.b.value
+      assert_equal  Integer , @ins.b.class
+      assert_equal  1 , @ins.b
     end
     def test_to_risc
       comp = @compiler.to_risc