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.
changed build to not do the I2C checks.
Expose debug flag to be controllable from Python bindings
Control wiringPiDebug flag rather than own
Merge branch 'master' of git://git.drogon.net/wiringPi