Bump deps
Remove notes.txt
Update Pure & make grid responsive for mobile

Not sure WTF was going on with Pure 0.4.2, but with 0.5.0 the responsive
grid stuff actually works.
Remove "Hang on, note still loading" text

This makes the one-frame flash before async data comes in less
noticeable.
Add per-component debounce and setTimeout

This allows us to do the "when you stop typing for 500 ms, flush edits
to PouchDB" logic, but also flush any pending edits immediately when the
component unmounts.

This fixes a bug I had described as:

> Stop typing in a note, then quickly return to folder list. The
  summary of the note is stale, and never updates. I need some way to
  keep track of pending actions and flush before leaving edit mode

Maybe this is overengineered, there's a better solution, etc., not sure.
The way the debounced function is created (in componentWillMount) is a
bit ugly and seems fragile, as a FIXME comment notes. For now it works.