Have m3_common auto-detect ICE serial port
Have m3_common auto-detect ICE serial port

I got tired of typing this all the time. It attempts to make
reasonable guesses if one isn't provided directly.

lab11/M-ulator,lab11/M-ulator,lab11/M-ulator,lab11/M-ulator,lab11/M-ulator,lab11/M-ulator,lab11/M-ulator