Looks for the next valid integer in the incoming serial. The function terminates if it times out (see Serial.setTimeout()).
Serial.parseInt() inherits from the Stream utility class.
Initial characters that are not digits or a minus sign, are skipped;
Parsing stops when no characters have been read for a configurable time-out value, or a non-digit is read;
If no valid digits were read when the time-out (see Serial.setTimeout()) occurs, 0 is returned;
Serial: serial port object. See the list of available serial ports for each board on the Serial main page.
skipChar: used to skip the indicated char in the search. Used for example to skip thousands divider.
long : the next valid integer