Addresses an issue where IE8 does not properly handle the RegExp in _parseTag, causing folding not to work for the XML mode (or modes that inherit XML). Tested XML mode in IE8/9 and major browsers. Should resolve ajaxorg/ace#1384
Merge pull request #1394 from rgriffith/ie8_xml_folding_fix

Addresses an issue where IE8 does not properly handle the RegExp in _par...