A bunch of bug fixes, performance improvements, and new api methods.

Bug fixes:
-  watch listeners not always firing
-  collapse button in array editor replaced with span when toggling
-  collapse button in array editor added extra line break when toggling
-  collapsed option broken for arrays

Performance improvements:
-  only a single 'change' event is now fired for each interaction with the form, regardless of interrelated templates, etc.
-  replaced internal DOM events with simple method calls when bubbling up changes.
-  simplified watched fields logic

New API methods:
-  watch, unwatch - Get alerted whenever a specific field changes

  ```js
  editor.watch('path.to.field',function() { /*...*/ });
  editor.unwatch('path.to.field',my_function);
  ```

-  getEditor - Get a reference to editor objects

  ```js
  var mystring = editor.getEditor('path.to.mystring');
  mystring.setValue('test');
  console.log(mystring.getValue());
  ```