Move fontfeature import statement

[NightFurySL2001]

Fix #56 ?

[typemytype]

this is not a conditional import, test if the package is available and decide

but the import issues with fontFeatures has been resolved upstream (no need for numpy anymore)

[typemytype]

should be something like:

try:
    from fontFeatures.ttLib import unparse
    _haveFontFeatures = True
except ImportError:
    _haveFontFeatures = False
    
def extractOpenTypeFeatures(source):
    if _haveFontFeatures:
        return unparse(source).asFea()
    return ""

[benkiel]

@typemytype if my change to your sample looks good to you, I'll merge and push an update

[typemytype]

thanks Ben!!