reads the serial port line by line

[Foadsf]

following these discussions:

1. https://twitter.com/fsfarimani/status/1101466971546284032
2. https://stackoverflow.com/questions/54934867/replicate-arduinos-serial-monitor-on-scilab-consol-to-read-a-pair-of-comma-sepe
3. https://stackoverflow.com/questions/54935990/read-the-latest-line-of-a-serial-port
4. https://groups.google.com/forum/#!topic/comp.lang.tcl/s5wcIAXft1M
5. https://www.reddit.com/r/electronics/comments/awkoka/creating_a_virtual_arduino_in_simulide_and_serial/
6. https://sourceforge.net/p/simulide/discussion/general/thread/a53c097f6a/#34c6/7d5f/a80d/7081/aeda