BlockDriver SerialUSB changes
=============================

0.01  21 Dec 2017  PRE
  - Created. Needs SerialUSB module 0.08 or later.

0.02  22 Jan 2018  PRE
  - Now reports error when port not available (rather than crashing).

0.03  11 Jun 2020  PRE
  - Now uses SerialUSB 0.10.
  - Now correctly reads device serial number (when available).

0.04  16 Jun 2020  PRE
  - Various bugfixes.

0.09  07 Jul 2020  PRE
  - Various bugfixes.
  - Stable release.