Ignore `.DS_Store` files.
Add a method to re-render the UI.

In certain circumstances, Gmail may have data available but not immediately render it.
This method forces a re-render.
Give `rerender` a callback.

So that, for instance, clients can scroll to the bottom of conversations after re-rendering
them.
Fixup documentation for `rerender`.
Merge pull request #114 from mixmaxhq/jeff/refresh

Add a method to re-render the UI.