README.txt fixups.
README.txt fixups.

Signed-off-by: Marti Bolivar <35e491f5b70a779e5455b1f9617e0073292369ca@leaflabs.com>

OpenMusicKontrollers/chimaera_firmware,OpenMusicKontrollers/chimaera_firmware,OpenMusicKontrollers/chimaera_firmware