Spurious package imports added

[anentropic]

After running waterloo on one file I found these imports:

from rest_framework import serializers
from serializers import Serializer

I believe this is probably the result of originally having:

from rest_framework import serializers

def some_func(arg):
    """
    Args:
        arg (serializers.Serializer)
    """
    ...

...but we already had a matching import and should not have added from serializers import Serializer

[anentropic]

fixed by #46