Fix bugs preventing OHIF Viewer usage

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);