Send installed language data to the plugin and theme update-check endpoints.

Introduces wp_get_installed_language_data() and wp_get_pomo_file_data().

see #18200.

Built from https://develop.svn.wordpress.org/trunk@25520


git-svn-id: http://core.svn.wordpress.org/trunk@25440 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Twelve: update code comments to reflect WP inline docs standards. Props DrewAPicture, see #25256.
Built from https://develop.svn.wordpress.org/trunk@25521


git-svn-id: http://core.svn.wordpress.org/trunk@25441 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Thirteen: update code comments to reflect WP inline docs standards. Props DrewAPicture, see #25256.
Built from https://develop.svn.wordpress.org/trunk@25522


git-svn-id: http://core.svn.wordpress.org/trunk@25442 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Twenty Fourteen: remove `rem` units, props iamtakashi. Fixes #25366.
Built from https://develop.svn.wordpress.org/trunk@25523


git-svn-id: http://core.svn.wordpress.org/trunk@25443 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Inline documentation for WP_Dependencies and _WP_Dependency classes.

Props kitchin for the initial patch.
Fixes #23914.

Built from https://develop.svn.wordpress.org/trunk@25524


git-svn-id: http://core.svn.wordpress.org/trunk@25444 1a063a9b-81f0-0310-95a4-ce76da25c4cd