a port for python3
add some ifdefs to make it compile on python2
Merge remote-tracking branch 'upstream/master'
Merge pull request #1 from rpodgorny/master

Python 3 fixes
Python 2 back compat fixes
Merge branch 'master' of https://github.com/Gadgetoid/py-spidev
Merge pull request #12 from Gadgetoid/master

Fixed fixes for Python 2 & 3