Updating the iframe src when the iframe isnt visible in IE8 causes a
view disconcerting font glitch (and it slows down navigation anyway),
so if the iframe isnt visible, delay setting the src until it is
It is now possible to change the threeColumnLayout width options for the
columns via entwine property LayoutOptions and accessor methods.
Thanks @robert-h-curry, @clarkepaul for contributing!
Introduces a preview window that appears when the screen is wide enough,
removes old preview button, adds a draft-public switch, adds variety of
preview options which are not hooked up yet.
Goes along with cms commit fa3738a9f4c5181eabf18a77ca89792d31592250
