include build & test spec files into jshint
fix semicolons & commas, pleasing jshint
unit test Class inheritance
switch to Rauschmayer's Class inheritance

John Resig's Class inheritance is quite complicated on getting
a class from an instance, prototype of an instance, & on getting
construtor function from an instance
adjust accordingly to new Class inheritance

- Classes use constructor() instead of init()
- instance's prototype & constructor just work!
- Pass unit test so far