LMIC library is outdated and LMIC debugging doesn't work

[JeroenvIS]

The LMIC library included with this platform is quite old, it hasn't been updated in two years. On the version that you're including now, it's impossible to compile with LMIC debugging enabled, as that is not supported on SAMD architecture with this old library. That has been fixed upstream though.

[JeroenvIS]

Upgrading LMIC to upstream 1.5.0+arduino3 makes it possible to compile with LMIC debugging enabled, when using Arduino core 1.6.x. With Arduino core 1.8.x, a minor additional fix to LMIC is needed. See matthijskooijman/arduino-lmic#270 for more details.