Disable external entities in ID3.

Built from https://develop.svn.wordpress.org/trunk@29378


git-svn-id: http://core.svn.wordpress.org/trunk@29156 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Media modal/grid: get the proper .attachment width in arrow navigation. Props avryl, see #27423.
Built from https://develop.svn.wordpress.org/trunk@29379


git-svn-id: http://core.svn.wordpress.org/trunk@29157 1a063a9b-81f0-0310-95a4-ce76da25c4cd