Revert use of 'open "iOS Simulator"' back to use of Instruments.

The use of "open" is causing "Invalid Device State" errors; this is probably because the iOS Simulator can only really launch one instance
at a time, and Instruments knows how to shutdown the previous instance.

lib/simctl-extensions.js

@@ -30,21 +30,9 @@ var shell = require('shelljs'),
 
 
 var extensions = {
-	startByApp : function(appName, deviceid) {
-        var command = 'open -a "' + appName + '"';
-        if (!deviceid) {
-            return shell.exec(command, { silent: true } );
-        } else {
-            command += util.format(command + ' --args -CurrentDeviceUDID %s', deviceid);
-            return shell.exec(command, { silent: true } );
-        }
-	},
-
     start : function(deviceid) {
-		// try "iOS Simulator" first (Xcode 6), if that fails, try "Simulator" (Xcode 7)
-		if (extensions.startByApp('iOS Simulator', deviceid).code !== 0) {
-			extensions.startByApp('Simulator', deviceid);
-		}
+         var command = util.format('xcrun instruments -w "%s"', deviceid);
+         return shell.exec(command, { silent: true } );
      },
 
     log : function(deviceid, filepath) {

package.json

@@ -1,6 +1,6 @@
 {
   "name": "simctl",
-  "version": "0.0.8",
+  "version": "0.0.9",
   "description": "library for Xcode simctl utility on OS X",
   "repository": {
     "type": "git",