Fade LEDs.
Copy slip-uart1.c from cpu/mc1322x
From IPv6 testing at Redwire
Copy improvements from bitbang-adf7023, commit da0116c.
Dump sent and received packets when ADF7023_VERBOSE >= 5.
Define NEWLINE.
Add preliminary button support.
Add ADF7023_VERBOSE level 7 for command, status, and interrupt info.