add vt200Mouse to rxvt because it supports it.

lib/program.js

@@ -2657,6 +2657,7 @@ Program.prototype.enableMouse = function() {
   // rxvt does not support the X10 UTF extensions
   if (this.term('rxvt')) {
     return this.setMouse({
+      vt200Mouse: true,
       x10Mouse: true,
       allMotion: true
     }, true);