Added hotkey support to viewerbase

Packages/viewerbase/lib/setActiveViewport.js

@@ -0,0 +1,20 @@
+setActiveViewport = function(element) {
+    if (!element) {
+        return;
+    }
+
+    var viewportIndex = $('.imageViewerViewport').index(element);
+
+    // When an ActivateViewport event is fired, update the Meteor Session
+    // with the viewport index that it was fired from.
+    Session.set("activeViewport", viewportIndex);
+
+    // Add the 'active' class to the parent container to highlight the active viewport
+    $('#imageViewerViewports .viewportContainer').removeClass('active');
+    $(element).parents('.viewportContainer').addClass('active');
+
+    // Finally, enable stack prefetching and hide the reference lines from
+    // the newly activated viewport
+    enablePrefetchOnElement(element);
+    displayReferenceLines(element);
+};