integration-tests for various webpack-scenarios

related to #1553

- registering helpers on an instance retrieved via
  `import`, compiling the template on an instance
   retrieved via `require`
- using `@roundingwellos/babel-plugin-handlebars-inline-precompile` to load plugins inline

integration-testing/webpack-test/src/handlebars-require-vs-import-test.js

@@ -0,0 +1,10 @@
+import * as HandlebarsViaImport from 'handlebars';
+const HandlebarsViaRequire = require('handlebars');
+import {assertEquals} from './lib/assert';
+
+HandlebarsViaImport.registerHelper('loud', function(text) {
+    return text.toUpperCase();
+});
+
+const template = HandlebarsViaRequire.compile('Author: {{loud author}}');
+assertEquals(template({author: 'Yehuda'}), 'Author: YEHUDA');