Work on refactoring measurements out of Lesion Tracker package

- Removed AssociatedStudies Collection
- Measurement API is generated from configuration files
- Data exchange methods are defined in configuration

LesionTracker/server/dropAllCollections.js

@@ -0,0 +1,14 @@
+// Temporary fix to drop all Collections on server restart
+// http://stackoverflow.com/questions/23891631/meteor-how-can-i-drop-all-mongo-collections-and-clear-all-data-on-startup
+Meteor.startup(() => {
+    console.warn('Dropping all Collections!');
+    Object.keys(global).forEach((key) => {
+        const object = global[key];
+        if (object instanceof Meteor.Collection) {
+            if (!(/^server|currentServer$/).test(object._name)) {
+                console.warn(`Dropping: ${object._debugName}`);
+                object.remove({});
+            }
+        }
+    });
+});