Lots of changes here. Added new I2C test code, a new serialTest program,

and developed the new ISR - Interrupt Service Routine
handler - much easier than the old waitForInterrupt code!

Minor tweaks to the gpio program to recognise the environment variable
WIRINGPI_DEBUG too, and removed the printing of the errors from the
main wiringPi setup routines (and added some new ones!)

gpio/Makefile

@@ -30,7 +30,7 @@ INCLUDE	= -I/usr/local/include
 CFLAGS	= $(DEBUG) -Wall $(INCLUDE) -Winline -pipe
 
 LDFLAGS	= -L/usr/local/lib
-LIBS    = -lwiringPi
+LIBS    = -lwiringPi -lpthread
 
 # May not need to  alter anything below this line
 ###############################################################################