add docs, rename classes for clarity

src/app/core/data/change-analyzer.ts

@@ -0,0 +1,20 @@
+import { NormalizedObject } from '../cache/models/normalized-object.model';
+import { Operation } from 'fast-json-patch/lib/core';
+
+/**
+ * An interface to determine what differs between two
+ * NormalizedObjects
+ */
+export interface ChangeAnalyzer<TNormalized extends NormalizedObject> {
+
+  /**
+   * Compare two objects and return their differences as a
+   * JsonPatch Operation Array
+   *
+   * @param {NormalizedObject} object1
+   *    The first object to compare
+   * @param {NormalizedObject} object2
+   *    The second object to compare
+   */
+  diff(object1: TNormalized, object2: TNormalized):  Operation[];
+}