Factored PDP-11 drive controller logic into a device-independent superclass (drive.js) and a device-dependent subclass (rk11.js); the RL11 controller is ready to be factored next

modules/pdp11/lib/debugger.js

@@ -59,7 +59,7 @@ if (NODE) {
  *      nBase:(number|undefined),
  *      sCmd:(string|undefined),
  *      aCmds:(Array.<string>|undefined)
- * }} DbgAddrPDP11
+ * }}
  */
 var DbgAddrPDP11;