Fix IrcUtil::messageToHtml(): nested color spans
Fix IrcUtil::messageToHtml(): nested color spans

Keep count of the depth of nested spans and handle
it gracefully when coloring span is reset

communi/communi-desktop,communi/communi-symbian,jpnurmi/communi-desktop,communi/communi-symbian,communi/communi-symbian,gdamjan/communi-desktop,communi/communi-desktop,communi/communi-symbian,sevanteri/communi-desktop