TwentyFifteen:
- Fix image caption alignment in the editor.
- Remove unused var from functions.js.
Also includes few images that were shrunk a bit when running grunt precommit.
Fixes #30493.

git-svn-id: https://develop.svn.wordpress.org/trunk@30562 602fd350-edb4-49c9-b593-d223f7449a82
Update `embedded.png` after running `grunt imagemin`.

After [30059] and [30079] we still had four images which could be minified. Three of them are handled by [30562], the last one by this.

fixes #30141.

git-svn-id: https://develop.svn.wordpress.org/trunk@30563 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: a shorter header on small screens when there is no header text or header image looks more correct.

Props iamtakashi, fixes #30326.




git-svn-id: https://develop.svn.wordpress.org/trunk@30564 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: pinching to zoom in on landscape on iPads is breaking the layout with the sticky sidebar. Providing a one-column view on those screens looks good and will likely prevent other bugs we don't even know about.

Props iamtakashi, fixes #30366.




git-svn-id: https://develop.svn.wordpress.org/trunk@30565 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: prevent too-wide tables from popping out of posts.

Props iamtakashi, fixes #30420



git-svn-id: https://develop.svn.wordpress.org/trunk@30566 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: remove unneeded custom header admin callbacks.

Props philiparthurmoore, fixes #30432.



git-svn-id: https://develop.svn.wordpress.org/trunk@30567 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: correct number of menus used in comments

Props jeherve, see #30149



git-svn-id: https://develop.svn.wordpress.org/trunk@30568 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: docs correction and cleanup.

Props DrewAPicture, see #30149.



git-svn-id: https://develop.svn.wordpress.org/trunk@30569 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: make sure the 'says:' in comments is readable by a screen-reader.

Fixes #30479.



git-svn-id: https://develop.svn.wordpress.org/trunk@30570 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: update the .pot file.

Props iamtakashi, fixes #30433.



git-svn-id: https://develop.svn.wordpress.org/trunk@30571 602fd350-edb4-49c9-b593-d223f7449a82
Twenty Fifteen: docs correction.

Props rachelbaker, DrewAPicture, fixes #30456



git-svn-id: https://develop.svn.wordpress.org/trunk@30572 602fd350-edb4-49c9-b593-d223f7449a82
Merge branch 'master' of git://develop.git.wordpress.org