[Snek] [keith-packard/snek] 633494: snekde: Make autobaud detection fancier

[Keith Packard]

  Branch: refs/heads/main
  Home:   https://github.com/keith-packard/snek
  Commit: 633494e7d19e1d944a34fe89953b9150c4f34275
      https://github.com/keith-packard/snek/commit/633494e7d19e1d944a34fe89953b9150c4f34275
  Author: Keith Packard <keithp at keithp.com>
  Date:   2022-03-27 (Sun, 27 Mar 2022)

  Changed paths:
    M snekde/snekde.py

  Log Message:
  -----------
  snekde: Make autobaud detection fancier

Put the autobaud code in a separate thread. Try it twice; once after
100ms and once after another 1.5 seconds to allow devices without boot
loaders to start quickly while still supporting devices with boot
loaders that delay for 1.5 seconds.

Signed-off-by: Keith Packard <keithp at keithp.com>