New Client: stable (#8426)

* try to freeze content object

* deep freeze the content object, start to implement stable

* freeze at the /common level

* go back to freezing content only on the client

* use deep-frezze-strict to support phantomjs

* use own version of deepFreeze

* update comment about deepFreeze

test/client/unit/specs/libs/deepFreeze.spec.js

@@ -0,0 +1,25 @@
+import deepFreeze from 'client/libs/deepFreeze';
+
+describe('deepFreeze', () => {
+  it('works as expected', () => {
+    let obj = {
+      a: 1,
+      b () {
+        return this.a;
+      },
+      nested: {
+        c: 2,
+        nestedTwice: {
+          d: 1,
+        },
+      },
+    };
+
+    let result = deepFreeze(obj);
+    expect(result).to.equal(obj);
+
+    expect(Object.isFrozen(obj)).to.equal(true);
+    expect(Object.isFrozen(obj.nested)).to.equal(true);
+    expect(Object.isFrozen(obj.nested.nestedTwice)).to.equal(true);
+  });
+});