When `$type` is `atom` in `get_the_category_rss()`, use `get_bloginfo_rss( 'url' )` when setting the `scheme` attribute for the `<category>` node.

Props ejdanderson.
Fixes #24444.


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Add `.dfxp` and `.srt` files to mime-type whitelist in `wp_get_mime_types()`. They are both captioning formats supported by MediaElement.

Props joedolson.
Fixes #27643.


Built from https://develop.svn.wordpress.org/trunk@28259


git-svn-id: http://core.svn.wordpress.org/trunk@28087 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Move 'home' option to the top of populate_options().

fixes #28141.

Built from https://develop.svn.wordpress.org/trunk@28260


git-svn-id: http://core.svn.wordpress.org/trunk@28088 1a063a9b-81f0-0310-95a4-ce76da25c4cd