[development] Created vs modified

When editing a node you are given the opportunity to change the Authored by and Authored on fields. In many cases I have multiple people changing pages and would rather show Changed by and Changed on, but both should be present in the node. So there are really two changes necessary. One to add the new fields and default them to the current logged on person and current date and the other to somewhere in settings say whether the created or changed info should be shown. Currently you can either show created or not.