bind correct this context to event

[dadigu]

The angular froala implementation hooks into the initialized event and passes it on. but the editor context is missing.

According to froala documentation you should be able to access the editor instance via this in most events.

new FroalaEditor('.selector', {
  events: {
    'initialized': function () {
      // Do something here.
      // this is the editor instance.
      console.log(this);
    }
  }
});

Right now this is undefined but this PR will fix this issue