Added additional tests for alternate constructors

For those objects built with the alternate constructors / IntroJs.Factory functions, test a subset of the IntroJs object's functions to ensure the IntroJs objects are the correct type.

intro.js/intro.js-tests.ts

@@ -70,3 +70,11 @@ intro.start()
     })
     .addHints()
     .clone();
+
+introWithElement.start()
+    .exit()
+    .clone();
+    
+introWithQuerySelector.start()
+    .exit()
+    .clone();