Changed buffer size in serialReader().
Reverted changes of serial library. Removed return value control of Serial::SerialImpl::close() of unix.cc and win.cc
Updated Serial::SerialImpl::flushInput() & Serial::SerialImpl::flushOutput() functions in win.cc file.
Updated flushInput and flushOutput in serialReader in order to remove unecessary data for both Windows & Linux OS.
Removed serialPort.flush and added serialPort.flushInput / serialPort.flushOutput in flushBuffer function.