Now that the upstream maintainer has abandoned this project without
establishing another maintainer, its difficult to choose an appropriate
version number. Going with 2.60 for now, as this only has incremental
changes to support 4B.
(cherry picked from commit 9aed9a4415)
Fixed some compiler warnings.
New wiringPi version mechanism.
Put 4800 baud (back) into the system.
Re-added piBoardRev (really an alias of piGpioLayout())