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

Packages/ohif-viewerbase/lib/helpers/formatNumberPrecision.js

@@ -0,0 +1,8 @@
+/**
+ * A global Blaze UI helper to format a float value to a specified precision
+ */
+UI.registerHelper('formatNumberPrecision', function(context, precision) {
+    if (context) {
+        return parseFloat(context).toFixed(precision);
+    }
+});