Add hooks to the wpeditimage tinymce plugin and to the image details portion of the media modal.
- Add wp.media.events which is intended to be a global media event bus.
- Add a post-render event to the ImageDetails view that third-party code can leverage to add subviews.
- Performance improvement for the initialization of the PostImage model.
- A bit more markup to the image details template to make it easier to add a view to the advanced options.
Props gcorne, fixes #27698

git-svn-id: https://develop.svn.wordpress.org/trunk@28095 602fd350-edb4-49c9-b593-d223f7449a82