Fix screenshot on index page not resizing in IE.

Looks like IE disregards the img width attribute now. Switching to CSS
width causes IE to shrink the screenshot properly.
IE8 fixes: add trim(), avoid js keywords.

Using javascript reserved keywords as a function name doesn't work in
IE8 (delete and new in this case). Since we're heavily dependent on
javascript, the site just shows a blank page when IE8 encounters such
javascript errors. Renaming the functions as a workaround. Also renamed
a variable, just in case.

IE8 doesn't implement trim(), added a hack to implement trim() if the
function doesn't exist.

Also will now display warnings about outdated browsers if using IE less
than 9. Quick testing shows that while the site does appear to work in
IE8, it still throws errors in the javascript console. IE9 appears to
work without those errors. I can't quite be sure that *everything* works
in IE8, so I've upped the requirement to 9 to be safe.