feature request: pop out markdown preview

[atomi]

Since the main use of the markdown preview is to review documentation, I think having a pop out pane just for the preview would be really really handy. I think most people would prefer a minimal pop-out without the bulky container or tabs.

[dnorthup-ums]

Given that this is now handled by the (also core) https://github.com/atom/markdown-preview package I suggest closing this issue.