Populating evolved features is slow

[zachwooddoughty]

We talked about this today, but the population of evolved features seems to take a disproportionate amount of time -- like an hour for 50 docs.

evolved_feature_three (as example) has an _init method that calls self.get_feature_vectors() on the necessary features, and then saves that information to self.features["evolved_feature_three"]. Each query of evolved_feature_three grabs the necessary values from the self.features hash, and does a simple addition/subtraction combination of the values. The code is below
https://github.com/NoahCarnahan/plagcomps/blob/master/intrinsic/featureextraction.py#L614

Why does this take so long?