gpio.c: enhanced Python-specific code
gpio.c: enhanced Python-specific code

This further enhances fix introduced by commit 0836067
by adding Python 3 support and correcting Python version
hex string used in compiler directives.

Signed-off-by: Alex Tereschenko <c1573d8a2714f7b294fae3af1bb5e489479ca966@gmail.com>
Signed-off-by: Brendan Le Foll <3e0e8c4069934e8b47d99704927a85c66c0ceb33@intel.com>

KurtE/mraa,ncrastanaren/mraa,anonymouse64/mraa,KurtE/mraa,whbruce/mraa,alext-mkrs/mraa,Pillar1989/mraa,KurtE/mraa,arfoll/mraa,ncrastanaren/mraa,stefan-andritoiu/mraa-gpio-chardev,ProfFan/mraa,malikabhi05/mraa,yongli3/mraa,jontrulson/mraa,arfoll/mraa,stefan-andritoiu/mraa,yongli3/mraa,arunlee77/mraa,whbruce/mraa,alext-mkrs/mraa,ncrastanaren/mraa,g-vidal/mraa,tripzero/mraa,malikabhi05/mraa,g-vidal/mraa,petreeftime/mraa,anonymouse64/mraa,Propanu/mraa,Jon-ICS/mraa,ncrastanaren/mraa,intel-iot-devkit/mraa,malikabhi05/mraa,jontrulson/mraa,sergev/mraa,Hbrinj/mraa,intel-iot-devkit/mraa,stefan-andritoiu/mraa,KurtE/mraa,alext-mkrs/mraa,jontrulson/mraa,petreeftime/mraa,andreivasiliu2211/mraa,arunlee77/mraa,KurtE/mraa,spitfire88/mraa,stefan-andritoiu/mraa-gpio-chardev,tripzero/mraa,Propanu/mraa,arfoll/mraa,malikabhi05/mraa,sergev/mraa,stefan-andritoiu/mraa,Propanu/mraa,arunlee77/mraa,stefan-andritoiu/mraa,malikabhi05/mraa,sergev/mraa,sergev/mraa,Propanu/mraa,stefan-andritoiu/mraa-gpio-chardev,andreivasiliu2211/mraa,stefan-andritoiu/mraa-gpio-chardev,arfoll/mraa,yongli3/mraa,Jon-ICS/mraa,Propanu/mraa,arunlee77/mraa,intel-iot-devkit/mraa,andreivasiliu2211/mraa,jontrulson/mraa,Hbrinj/mraa,alext-mkrs/mraa,alext-mkrs/mraa,jontrulson/mraa,whbruce/mraa,Pillar1989/mraa,ProfFan/mraa,w4ilun/mraa,w4ilun/mraa,Hbrinj/mraa,arfoll/mraa,whbruce/mraa,tripzero/mraa,petreeftime/mraa,ProfFan/mraa,ProfFan/mraa,stefan-andritoiu/mraa,Pillar1989/mraa,spitfire88/mraa,stefan-andritoiu/mraa-gpio-chardev,g-vidal/mraa,yongli3/mraa,intel-iot-devkit/mraa,intel-iot-devkit/mraa,sergev/mraa,g-vidal/mraa,w4ilun/mraa,Jon-ICS/mraa,spitfire88/mraa,anonymouse64/mraa,petreeftime/mraa,Hbrinj/mraa,spitfire88/mraa,yongli3/mraa,ncrastanaren/mraa,w4ilun/mraa,g-vidal/mraa,andreivasiliu2211/mraa