Allow language specified by the WPLANG constant (but not installed) to be chosen.

fixes #29456.

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git-svn-id: http://core.svn.wordpress.org/trunk@29466 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Editor scrolling: Avoid jumping to the cursor when modifier and scrolling keys are pressed.

fixes #29485.

Built from https://develop.svn.wordpress.org/trunk@29692


git-svn-id: http://core.svn.wordpress.org/trunk@29467 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Editor scrolling: Remember and restore scroll position for visual and text modes.

This prevents the editor from jumping off screen when the rendered visual content is significantly taller than plain text, e.g. when there are views present.

This is also a close restoration of 3.9 behavior, some of which was browser-specific.

props avryl.
fixes #29338.

Built from https://develop.svn.wordpress.org/trunk@29693


git-svn-id: http://core.svn.wordpress.org/trunk@29468 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Language Pack Upgrader: Allow to disable asynchronously translation updates.

* Don't touch VCS installs.
* Use the `async_update_translation` filter (which corresponds exactly to `auto_update_translation`) to entirely disable it, or based on the update offer. 

props nacin, ocean90.
fixes #28571.
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git-svn-id: http://core.svn.wordpress.org/trunk@29469 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Restore the post type's view_item label for preview links that don't submit the changes.

fixes #28350.
Built from https://develop.svn.wordpress.org/trunk@29695


git-svn-id: http://core.svn.wordpress.org/trunk@29470 1a063a9b-81f0-0310-95a4-ce76da25c4cd
4.0-RC2.

Built from https://develop.svn.wordpress.org/trunk@29696


git-svn-id: http://core.svn.wordpress.org/trunk@29471 1a063a9b-81f0-0310-95a4-ce76da25c4cd