Integrate sinon's assertion API into QUnit

Fixes issue elwayman02#222 

This is a big win as sinon's assertion API is far superior, more readable, and offers better messaging then doing so manually.

addon-test-support/index.js

@@ -1,4 +1,6 @@
 import { createSandbox, restoreSandbox } from './sinon-sandbox';
+import { commonConfig } from '../utils/config';
+let initializedCommonConfig;
 
 /**
  * Allows for creating and restoring a global sinon sandbox per test. This is
@@ -9,6 +11,10 @@ import { createSandbox, restoreSandbox } from './sinon-sandbox';
  * @public
  */
 export default function setupSinon(testEnvironment = self.QUnit) {
+  if (!initializedCommonConfig) {
+    initializedCommonConfig = true;
+    commonConfig();
+  }
   testEnvironment.testStart(createSandbox);
   testEnvironment.testDone(restoreSandbox);
 }