Media Grid/Modal Keyboard navigation improvements:

* Add focus to arrows on Next/Previous in the grid's modal on left/right keypress, and add the necessary CSS for `:focus`
* When in a disabled input in the grid modal, allow the left/right keys to work
* Make the image editor return a `$.Deferred` so that there isn't a race condition with UI loading. 
* Assign focus when the edit image mode is rendered so that the modal can be closed on Esc press

Props wonderboymusic, adamsilverstein (for the initial patch).
See #23560.

Built from https://develop.svn.wordpress.org/trunk@29560


git-svn-id: http://core.svn.wordpress.org/trunk@29335 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add missing box-shadow for pingbacks in Dashboard Activity widget.

props chrisl27.
fixes #29198.
Built from https://develop.svn.wordpress.org/trunk@29561


git-svn-id: http://core.svn.wordpress.org/trunk@29336 1a063a9b-81f0-0310-95a4-ce76da25c4cd
`media.view.Attachment`: set all of the view attributes in the same hash.

See [29299], #23560.

Built from https://develop.svn.wordpress.org/trunk@29562


git-svn-id: http://core.svn.wordpress.org/trunk@29337 1a063a9b-81f0-0310-95a4-ce76da25c4cd
After [29543], the iframe sandboxes for media need to load Open Sans. Playlists look aggressively bad without it. Adds font styles for the body.

See #29048.

Built from https://develop.svn.wordpress.org/trunk@29564


git-svn-id: http://core.svn.wordpress.org/trunk@29338 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: don't auto-select attachments upon upload.

Props ocean90.
See #28842.

Built from https://develop.svn.wordpress.org/trunk@29565


git-svn-id: http://core.svn.wordpress.org/trunk@29339 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: after completing a Bulk action, switch from `select` to `edit` mode.

Fixes #28842.

Built from https://develop.svn.wordpress.org/trunk@29566


git-svn-id: http://core.svn.wordpress.org/trunk@29340 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: don't hide the uploader progress bar for individual items.

See [29527], #29037.

Built from https://develop.svn.wordpress.org/trunk@29567


git-svn-id: http://core.svn.wordpress.org/trunk@29341 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media Grid: after [29566], account for Trash and Delete.

See #28842.

Built from https://develop.svn.wordpress.org/trunk@29568


git-svn-id: http://core.svn.wordpress.org/trunk@29342 1a063a9b-81f0-0310-95a4-ce76da25c4cd