WP_HTTP: Allow developers to specify a Accept-Encoding header. Fixes #20142


git-svn-id: http://core.svn.wordpress.org/trunk@23600 1a063a9b-81f0-0310-95a4-ce76da25c4cd
WP_HTTP: Do not send a Accept-Encoding header when we're streaming to file, or decompression has been disabled by the caller, See #22913


git-svn-id: http://core.svn.wordpress.org/trunk@23601 1a063a9b-81f0-0310-95a4-ce76da25c4cd
WP_HTTP: Specifically mark a static function as being static



git-svn-id: http://core.svn.wordpress.org/trunk@23602 1a063a9b-81f0-0310-95a4-ce76da25c4cd