Add --python3ok option to setup.py
Add --python3ok option to setup.py

This allows us to run tests on Python 3.3+, while keeping
the error message we only support Python 2.

Change-Id: I7473a595a5acd464a74343f2d675f285033ec5b1

npdoty/pywikibot,Darkdadaah/pywikibot-core,happy5214/pywikibot-core,Darkdadaah/pywikibot-core,trishnaguha/pywikibot-core,hasteur/g13bot_tools_new,smalyshev/pywikibot-core,valhallasw/pywikibot-core,emijrp/pywikibot-core,hasteur/g13bot_tools_new,happy5214/pywikibot-core,hasteur/g13bot_tools_new,VcamX/pywikibot-core,PersianWikipedia/pywikibot-core,h4ck3rm1k3/pywikibot-core,xZise/pywikibot-core,npdoty/pywikibot,magul/pywikibot-core,wikimedia/pywikibot-core,darthbhyrava/pywikibot-local,wikimedia/pywikibot-core,jayvdb/pywikibot-core,jayvdb/pywikibot-core,icyflame/batman,TridevGuha/pywikibot-core,h4ck3rm1k3/pywikibot-core,magul/pywikibot-core