Add better error checking for Robot#halt

lib/robot.js

@@ -394,12 +394,22 @@ Robot.prototype.startDevices = function(callback) {
 Robot.prototype.halt = function(callback) {
   callback = callback || function() {};
 
+  if (!this.isRunning) {
+    return callback();
+  }
+
   var devices = _.map(this.devices, "halt");
   var connections = _.map(this.connections, "disconnect");
 
-  Async.parallel(devices, function() {
-    Async.parallel(connections, callback);
-  });
+  try {
+    Async.parallel(devices, function() {
+      Async.parallel(connections, callback);
+    });
+  } catch (e) {
+    var msg = "An error occured while attempting to safely halt the robot";
+    this.log("error", msg);
+    this.log("error", e.message);
+  }
 
   this.running = false;
 };

spec/lib/robot.spec.js

@@ -550,6 +550,8 @@ describe("Robot", function() {
         }
       });
 
+      bot.isRunning = true;
+
       device = bot.devices.ping;
       connection = bot.connections.loopback;