Modify to use the mrb_get_args() how to bind text
mrb_define_method -> mrb_define_class_method
Revert "mrb_define_method -> mrb_define_class_method"

This reverts commit a593a30227a217998c3a54bdd7e83cda7d8d6efd.
Cause error under case to use mrb_define_class_method.

module AAA
  def self.draw
-    set_fill
+   Kernel.set_fill
  end
end
Bind Color#inspect
Additional tests of constant

Bind Color::White, Black, Gray, Red, Green
Bind Color constant variable