Configure how fast the live preview should update

[rabol]

The live preview is a awesome feature, but it flashes a lot when you type, so it would be nice if one could say that the update should only happen after x ms of keyboard inactivity

[jackmcdade]

I think a better solution would be to find a better way to morph the iFrame or otherwise revise the logic to avoid the flash. Closing in favor of this approach.