Update styling for the Edit Image popup in TinyMCE

[azaozz]

As we are using this in 3.5, the css for the iframe would need some updating.

In 22447.patch:

• Load buttons.css in the popup's iframe.
• Match fonts with the rest of the admin.
• Add 2x for the align icons.

Also removes the "views" styling from the editor content css.

../../../../../../wp-admin/images/align-none-2x.png works, but isn't valid. We'll need to move those alignment icons into wp-includes to use it here.

koopersmith and I discussed converting this to be a template like everything else. Enables us to reuse existing styles and pieces of HTML to provide a better experience. But, only if we have time. Unfortunately we've approached the long tail of bugs, so this might not be the best use of our time.

Yes, the (old) Edit Image modal is the only place that uses these icons in 3.5. They are in wp-admin/images because of the old Upload/Insert modal that will be removed. The ../../../../../../wp-admin/images/... may look "ugly" but is the only safe way to reference the icons from wp-includes/js/tinymce/plugins/wpeditimage/css/editimage.css.

In 22586:

TinyMCE: fix styles, add 2x background icons and load buttons.css in the Edit Image modal, remove wp-view styles from content.css, add 2x icons for the popup buttons (for editing image and gallery), fixes #22447, see #21019