Drop six as a requirement; add six_shim.py (#618)

Author: willkg

bleach/six_shim.py

@@ -0,0 +1,19 @@
+"""
+Replacement module for what html5lib uses six for.
+"""
+
+import http.client
+import operator
+import urllib
+
+
+PY3 = True
+binary_type = bytes
+string_types = (str,)
+text_type = str
+unichr = chr
+viewkeys = operator.methodcaller("keys")
+
+http_client = http.client
+urllib = urllib
+urllib_parse = urllib.parse

setup.py

@@ -25,7 +25,6 @@ def get_version():
 
 INSTALL_REQUIRES = [
     # html5lib requirements
-    "six>=1.9.0",
     "webencodings",
 ]