- User-side read only copies *new* data, rather than *all* the data in the buffer.
  - Edge case where number of buffer rows = 1 & Obs is a scalar
  - Added dependencies for demos (minus psychopy, which is heavy w/o --no-deps)
  - Make `make_obs` available from `toon.input`
  - Prevent pickling issues when restarting an MpDevice (device's `self.Returns` isn't picklable)