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-dicom-services/server/DICOMWeb/getModalities.js

@@ -0,0 +1,21 @@
+DICOMWeb.getModalities = function(modality, modalitiesInStudy) {
+    var modalities = {};
+    if (modality) {
+        modalities = modality;
+    }
+
+    if (modalitiesInStudy) {
+        // Find vr in modalities
+        if (modalities.vr && modalities.vr === modalitiesInStudy.vr) {
+            for (var i = 0; i < modalitiesInStudy.Value.length; i++) {
+                var value = modalitiesInStudy.Value[i];
+                if (modalities.Value.indexOf(value) === -1) {
+                    modalities.Value.push(value);
+                }
+            }
+        } else {
+            modalities = modalitiesInStudy;
+        }
+    }
+    return modalities;
+};