Use Device.js to determine mobile editor use

Ref #2570
- Adds new library, device.js to determine if the user is on an ios mobile
  or tablet.

Gruntfile.js

@@ -509,6 +509,7 @@ var path           = require('path'),
                             'bower_components/showdown/src/showdown.js',
                             'bower_components/moment/moment.js',
                             'bower_components/keymaster/keymaster.js',
+                            'bower_components/device/lib/device.js',
                             'bower_components/jquery-ui/ui/jquery-ui.js',
                             'bower_components/jquery-file-upload/js/jquery.fileupload.js',
                             'bower_components/fastclick/lib/fastclick.js',

bower.json

@@ -4,6 +4,7 @@
     "backbone": "1.0.0",
     "codemirror": "4.0.1",
     "Countable": "2.0.2",
+    "device": "matthewhudson/device.js#5347a275b66020a0d4dfe9aad81a488f8cce448d",
     "ember": "1.5.0",
     "ember-data": "~1.0.0-beta.8",
     "ember-load-initializers": "git://github.com/stefanpenner/ember-load-initializers.git#0.0.1",

core/client/utils/codemirror-mobile.js

@@ -1,4 +1,4 @@
-/*global CodeMirror*/
+/*global CodeMirror, device*/
 import mobileUtils from 'ghost/utils/mobile-utils';
 import createTouchEditor from 'ghost/assets/lib/touch-editor';
 
@@ -24,7 +24,9 @@ setupMobileCodeMirror = function setupMobileCodeMirror() {
 };
 
 init = function init() {
-    if (mobileUtils.hasTouchScreen()) {
+    //Codemirror does not function on mobile devices,
+    // nor on any iDevice.
+    if (device.mobile() || (device.tablet() && device.ios())) {
         $('body').addClass('touch-editor');
 
         // make editor tabs touch-to-toggle in portrait mode