CHTMLpreview should detect IE<8 [was: MathJax 2.5 has broken IE 6/7 compatibility on Windows XP/Vista (v2.4 works, Win 7+ okay)]

Created by: thomastan

Math is getting replaced with [Math Processing Error]'s.

IE 8 on XP/Vista/7+ is fine. Problem is occurring on http://math.stackexchange.com/questions as well as my own site. I previously had a problem with IE 6-8 in v2.3 which got a speedy fix: #672 (closed)

Problems on: IE 6 XP; IE7 XP; IE7 Vista. IE8+ is unaffected.