Output errors to stderr

[justind000]

I was recently writing some simple cli bash scripts to automate testing my particle.io libraries. When there is an error, it doesn't appear in stderr.

To demonstrate: particle compile photon $d/ > /dev/null

Outputs nothing on error.

Whereas this: arduino-cli compile -b arduino:avr:pro:cpu=16MHzatmega328 $d > /dev/null Will display the error.