@gib: Sync new articles to old posts

To get the editorial team to transition to the new writing tool & force some QA work before flipping the switch, I'm adding the ability to sync to new articles to old posts. My intention is to switch them to writer ASAP, drop the old posting tool, enable articles across Force as a labs feature, and after Force QA flip the switch.

![cap](https://cloud.githubusercontent.com/assets/555859/5334554/6d91f0cc-7e61-11e4-8263-f05fbd73f0b6.gif)