sjm - 26 Mar 2006: 
	- Changed sleep(2) to sleep(3) to prevent the "resource temporarily 
	unavailable" error. Seems to be more of an issue with faster machines.
	- Included stdlib.h for the exit() function

sjm - 06 Apr 2017:
	- Fix uninitialised variable
	- Added utility to log up to 4 channels of discrete data
	- Updated copyright dates
