fix(user-preferences): Fix the issues with saving/retrieving user preferences in OHIFViewer

OHIFViewer/client/body.html

@@ -0,0 +1,3 @@
+<body>
+    <div id="notificationArea" class="notification-area"></div>
+</body>

OHIFViewer/client/body.styl

@@ -0,0 +1,2 @@
+body
+  background-color: black

Packages/ohif-hotkeys/client/classes/HotkeysManager.js

@@ -36,7 +36,7 @@ export class HotkeysManager {
         return new Promise((resolve, reject) => {
             if (this.storeFunction) {
                 this.storeFunction.call(this, storageKey, definitions).then(resolve).catch(reject);
-            } else if (Meteor.userId()) {
+            } else if (OHIF.user.userLoggedIn()) {
                 OHIF.user.setData(storageKey, definitions).then(resolve).catch(reject);
             } else {
                 Session.setPersistent(storageKey, definitions);
@@ -50,7 +50,7 @@ export class HotkeysManager {
         return new Promise((resolve, reject) => {
             if (this.retrieveFunction) {
                 this.retrieveFunction(contextName).then(resolve).catch(reject);
-            } else if (OHIF.user) {
+            } else if (OHIF.user.userLoggedIn()) {
                 try {
                     resolve(OHIF.user.getData(storageKey));
                 } catch(error) {

Packages/ohif-viewerbase/client/lib/WLPresets.js

@@ -153,7 +153,7 @@ class WindowLevelPresetsManager {
         return new Promise((resolve, reject) => {
             if (this.retrieveFunction) {
                 this.retrieveFunction.call(this).then(resolve).catch(reject);
-            } else if (OHIF.user) {
+            } else if (OHIF.user.userLoggedIn()) {
                 try {
                     resolve(OHIF.user.getData(WL_STORAGE_KEY));
                 } catch(error) {