Changed the build system to drop I2C for now. Seems to cause too many issues

on non Raspbian systems (and even on some Raspbian systems it would appear ):

fixed a timing issue on softTone
fixed some issues in wiringPisetup introduced when optimising the mmap calls.

README.TXT

@@ -0,0 +1,26 @@
+
+wiringPi README
+===============
+
+Please note that the official way to get wiringPi is via git from
+git.drogon.net and not GitHub.
+
+ie.
+
+  git clone git://git.drogon.net/wiringPi
+
+The version of wiringPi held on GitHub by "Gadgetoid" is used to build the
+wiringPython, Ruby, Perl, etc. wrappers for these other languages. This
+version may lag the official Drogon release.  Pull requests may not be
+accepted to Github....
+
+Please see
+
+  https://projects.drogon.net/raspberry-pi/wiringpi/
+
+for the official documentation, etc. and the best way to submit bug reports, etc.
+is by sending an email to projects@drogon.net
+
+Thanks!
+
+  -Gordon