fixed serial device name for Linux

[leoyinjou]

Issue: in Linux, p.name returns 'ttyACM0' for '/dev/ttyACM0' for example so p.open() will fail and exception will be triggered without useful debug messages.

Fix: using p.device will display the full name for both Windows COM* ports and Linux /dev/tty* ports. Verified functional on both. Not tested on Mac.

[c3charvat]

Was just looking for a solution to this very problem