In `wp.media.view.Settings::update()`, when handling checkboxes, check for a value of `'false'` in addition to casting `value` to boolean. `!! 'false'` evaluates to `true`.

Props adamsilverstein.
Fixes #23954.


Built from https://develop.svn.wordpress.org/trunk@28371


git-svn-id: http://core.svn.wordpress.org/trunk@28199 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Add `xps` and `oxps` extensions to list of supported document types.

More: http://en.wikipedia.org/wiki/Open_XML_Paper_Specification

Fixes #15697.


Built from https://develop.svn.wordpress.org/trunk@28372


git-svn-id: http://core.svn.wordpress.org/trunk@28200 1a063a9b-81f0-0310-95a4-ce76da25c4cd