Fixed "allwindows" screenshot with keyboard

This problem was discussed in the mailing groups 
> screenshot/allwindows returning "mashed-up" view

For reference see http://developer.apple.com/library/ios/#qa/qa1703/_index.html

I don't really like that `screenshot/allwindows` always returns image in the portrait orientation but changing that would break symbiote. I have added `screenshot/allwindows-rotated` which will return a screenshot rotated depending on current screen orientation.