@dzucconi: More wiring up/filling out Force posts

These are some minor changes on the Positron side to fix some small bugs and link the "Preview/View" button to Force.

Force PR: https://github.com/artsy/force/pull/1722

![cap](https://cloud.githubusercontent.com/assets/555859/5132680/d1cf8182-70cc-11e4-877e-5ef61f41badc.gif)