Update django-filter, remove unpublished backport

Author: Ryan P Kilby

rest_framework_filters/fields.py

@@ -1,10 +1,5 @@
 from django import forms
-
-# TODO: Remove when django-filter 0.12.0 is released
-try:
-    from django_filters import BooleanWidget
-except ImportError:
-    from .widgets import BooleanWidget
+from django_filters.widgets import BooleanWidget
 
 
 class BooleanField(forms.BooleanField):

rest_framework_filters/widgets.py

@@ -2,9 +2,7 @@
 # -*- coding: utf-8 -*-
 
 from setuptools import setup
-import re
 import os
-import sys
 
 
 def get_packages(package):
@@ -43,10 +41,9 @@ def get_package_data(package):
     packages=get_packages('rest_framework_filters'),
     package_data=get_package_data('rest_framework_filters'),
     zip_safe=False,
-    #test_suite='rest_framework.runtests.runtests.main',
     install_requires=[
         'djangorestframework',
-        'django-filter>=0.11.0',
+        'django-filter>=0.12.0',
     ],
     classifiers=[
         'Development Status :: 5 - Production/Stable',