Fix bugs preventing OHIF Viewer usage

OHIFViewer/client/components/viewer/viewer.html

@@ -1,4 +1,5 @@
 <template name="viewer">
+    {{#if Template.subscriptionsReady}}
     <div id="viewer">
         {{> studyBrowser }}
         <div class='viewerMain'>
@@ -6,4 +7,7 @@
             {{ > imageViewerViewports }}
         </div>
     </div>
+    {{else}}
+        {{>loadingText}}
+    {{/if}}
 </template>

OHIFViewer/client/components/viewer/viewer.js

@@ -68,7 +68,8 @@ Template.viewer.onCreated(function() {
     Session.set('activeViewport', ViewerData[contentId].activeViewport || 0);
 
     // Update the ViewerStudies collection with the loaded studies
-    ViewerStudies = new Meteor.Collection(null);
+    ViewerStudies.remove({});
+    
     this.data.studies.forEach(function(study) {
         study.selected = true;
         ViewerStudies.insert(study);