Syntax corrections and the ability to use without instantiation

- Fixes instantiation syntax error.
- Allows usage of Observable without the constructor e.g.
    MyClass.prototype = Object.create(Observer.prototype);
- Corrects typo _shouldBubble -> _eventsShouldBubble

- Why so many commits?! For some reason I had some rather substantial white space changes when I updated to the latest changes. I didn't want to pollute this pull request diff with whitespace, so I reverted them and tried again!