Adding modding folder with a hacked build.

modding/hacked/ss1/edit/undoable/cmd/Command.go

@@ -0,0 +1,15 @@
+package cmd
+
+import "github.com/inkyblackness/hacked/ss1/world"
+
+// Command describes an action that can be performed, undone, and redone.
+type Command interface {
+	// Do performs the action.
+	// An error is returned if the action could not be performed.
+	Do(modder world.Modder) error
+
+	// Undo reverses its action to restore the environment to the previous state.
+	// An error is returned if the action could not be successfully undone. The
+	// environment may not be in the state as before in an error occurred.
+	Undo(modder world.Modder) error
+}