add the 'add new category' when selecting a category on a blog engine

[rickybanister]

We require users to create a blog engine before creating their first blog post. If they create an engine specifying no categories, then go over to the blog and create their first post, giving it a first category, you must then go back to the engine and select that category. Headspin.

We should stick the 'add category' option in the select category dropdown when editing pagesettings, or creating a new page. Then the user goes to the blog admin and their category is already there for their post.

The interface should be EXACTLY the same as it is in the blog admin sidebar. Available on both the page settings and page creation form.

[boutell]

This can be done with aMultipleSelect's add feature

[rickybanister]

Just use the UI from the blog admin sidebar

[geoffd]

This is when:

• you are adding a new page and selecting a blog
• allowing an editor to add a category
• when you are in Page Settings

[tboutell]

This is a nice usability improvement but not a defect

[tboutell]

Done in [2985] [2986]

"add new category" is available for events, blogs and media. They all use the same partials and the same parent form class to get the job done, so no drifting implementations to worry about. Also, a_js_call is now available to engine settings partials in all cases (the engineSettingsSuccess template takes care of it after calling your partial) and there are no more script tags floating around in our own engine settings partials.

[tboutell]

Switched the cc to team on this fairly popular issue (the good news is that you can add new categories while editing page settings for media, blog and events pages now).