Add gallery settings to the media modal.

* Abstracts `wp.media.view.AttachmentDisplaySettings` into `wp.media.view.Settings` for managing lists of settings with button groups and select boxes. Settings can optionally be tied to a user setting (i.e. using `getUserSetting`).
* Adds `wp.media.view.Settings.AttachmentDisplay`.
* Adds `wp.media.view.Settings.Gallery`.

see #21390, #21815.


git-svn-id: http://core.svn.wordpress.org/trunk@22340 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Make gallery columns fallback a string, as the accepted values are strings. see #21390.


git-svn-id: http://core.svn.wordpress.org/trunk@22341 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Remove dead gallery settings code. see #21390.


git-svn-id: http://core.svn.wordpress.org/trunk@22342 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix positioning of attachment thumbnail overlays.

Prevents the overlay from blocking buttons inside the attachment preview, such as the remove button in the gallery editor.

see #21390.


git-svn-id: http://core.svn.wordpress.org/trunk@22343 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media JS: When editing a gallery, prevent attachments from being selected as they are removed. see #21390.


git-svn-id: http://core.svn.wordpress.org/trunk@22344 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media: Reduce button size for the link gallery setting. see #21390.


git-svn-id: http://core.svn.wordpress.org/trunk@22345 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Theme Translations: Allow for theme pomo files to be loaded from WP_LANG_DIR/themes/{$domain}-{$locale}.(p|m)o.
This directory format is what we have chosen for Language Packs (See #18200), but which is currently delayed.

By making this change, we can ship localised theme files within core for bundled themes, and avoid the issues associated with Theme Updates overwriting/removing the language files.

Fixes #18960



git-svn-id: http://core.svn.wordpress.org/trunk@22346 1a063a9b-81f0-0310-95a4-ce76da25c4cd
When receiving a HEAD request, die() right before we start outputting content.

* Content doesn't make sense for HEAD requests
* Saves wear and tear on the server
* Introduces a filter: exit_on_http_head (we send TRUE through it)

fixes #14348. props mbijon, mitchoyoshitaka.

git-svn-id: http://core.svn.wordpress.org/trunk@22347 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media: Update gallery editing to work with the new frame view. see #21390.


git-svn-id: http://core.svn.wordpress.org/trunk@22348 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Sync POMO with GlotPress

See http://glotpress.trac.wordpress.org/browser/trunk/pomo/


git-svn-id: http://core.svn.wordpress.org/trunk@22349 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Replace gp_endswith() with working implementation

In [22349] we introduced a call to gp_endswith(),
whcih doesn't exist in WordPress, only in GlotPress.

See #22337


git-svn-id: http://core.svn.wordpress.org/trunk@22350 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add Instagram oEmbed support. Props bananastalktome. Fixes #21704.


git-svn-id: http://core.svn.wordpress.org/trunk@22351 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Compress scripts/styles: 3.5-beta2-22352.

git-svn-id: http://core.svn.wordpress.org/trunk@22352 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Clean up [22347] a bit. see #14348

git-svn-id: http://core.svn.wordpress.org/trunk@22353 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix a PHP Notice when attempting to Add or remove capabilities from nonexistant roles. Props SergeyBiryukov. Fixes #18461


git-svn-id: http://core.svn.wordpress.org/trunk@22354 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fix typos in comments. Props SergeyBiryukov, see #22337


git-svn-id: http://core.svn.wordpress.org/trunk@22355 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Merge branch 'master' into ticket-6821-imagemagick