Minor changes for the CM3.

Fixed some compiler warnings.
New wiringPi version mechanism.
Put 4800 baud (back) into the system.
Re-added piBoardRev (really an alias of piGpioLayout())

version.h

@@ -0,0 +1,3 @@
+#define VERSION "2.36"
+#define VERSION_MAJOR 2
+#define VERSION_MINOR 36