RTL should use Tahoma, Hebrew should use Arial.

props yoavf.
see #24977.

Built from https://develop.svn.wordpress.org/trunk@26783


git-svn-id: http://core.svn.wordpress.org/trunk@26670 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Dashboard: set two columns as default for IE8 (as it doesn't support @media rules), see #25824.
Built from https://develop.svn.wordpress.org/trunk@26784


git-svn-id: http://core.svn.wordpress.org/trunk@26671 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Fake a "non-responsive" window width for IE < 9 when folding/unfolding the menu (old IE doesn't support @media), fixes #26458.
Built from https://develop.svn.wordpress.org/trunk@26785


git-svn-id: http://core.svn.wordpress.org/trunk@26672 1a063a9b-81f0-0310-95a4-ce76da25c4cd
Avoid a notice by checking that SCRIPT_DEBUG is defined before evaluating it in `register_admin_color_schemes()`.

See #26316.

Built from https://develop.svn.wordpress.org/trunk@26786


git-svn-id: http://core.svn.wordpress.org/trunk@26673 1a063a9b-81f0-0310-95a4-ce76da25c4cd