MAINT: Special-case python3.3/python3.4 correctly
MAINT: Special-case python3.3/python3.4 correctly

According to the article linked in the header, python3.3 and 3.4 need a
special flag to make sure the build environment is set up correctly.

This works together with util/appveyor/build.cmd.

rgommers/pywt,eriol/pywt,eriol/pywt,PyWavelets/pywt,kwohlfahrt/pywt,rgommers/pywt,grlee77/pywt,grlee77/pywt,kwohlfahrt/pywt,michelp/pywt,rgommers/pywt,eriol/pywt,PyWavelets/pywt,michelp/pywt,michelp/pywt,kwohlfahrt/pywt,rgommers/pywt