Support DEL in the REPL.

lib/readline.js

@@ -255,6 +255,11 @@ Interface.prototype._ttyWrite = function (b) {
         this._historyPrev();
       } else if (b[1] === 91 && b[2] === 66) { // down arrow
         this._historyNext();
+      } else if (b[1] === 91 && b[2] === 51 && this.cursor < this.line.length) { // delete right
+        this.line = this.line.slice(0, this.cursor)
+                    + this.line.slice(this.cursor+1, this.line.length)
+                    ;
+        this._refreshLine();
       }
       break;