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!)

examples/serialTest.c

@@ -0,0 +1,57 @@
+/*
+ * serialTest.c:
+ *	Very simple program to test the serial port. Expects
+ *	the port to be looped back to itself
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <wiringPi.h>
+#include <wiringSerial.h>
+
+int main ()
+{
+  int fd ;
+  int count ;
+  unsigned int nextTime ;
+
+  if ((fd = serialOpen ("/dev/ttyAMA0", 115200)) < 0)
+  {
+    fprintf (stderr, "Unable to open serial device: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+  if (wiringPiSetup () == -1)
+  {
+    fprintf (stdout, "Unable to start wiringPi: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+  nextTime = millis () + 300 ;
+
+  for (count = 0 ; count < 256 ; )
+  {
+    if (millis () > nextTime)
+    {
+      printf ("\nOut: %3d: ", count) ;
+      fflush (stdout) ;
+      serialPutchar (fd, count) ;
+      nextTime += 300 ;
+      ++count ;
+    }
+
+    delay (3) ;
+
+    while (serialDataAvail (fd))
+    {
+      printf (" -> %3d", serialGetchar (fd)) ;
+      fflush (stdout) ;
+    }
+  }
+
+  printf ("\n") ;
+  return 0 ;
+}