First part of patch for bug #81967,

First part of patch for bug #81967,

2007-08-12  Lukasz Byczynski <lukaszb@forcom.com.pl>

	* serial.c:

	- all changes are based on Windows .Net SerialPort behavior and
	this
	document: http://www.easysw.com/~mike/serial/serial.html
	- removed wrong default values from open_serial
	- added timeout detection in write_serial
	- added proper parameters setting in set_attributes

svn path=/trunk/mono/; revision=83921