Initial python3 changes

Mostly just updating libraries, removing string encoding/decoding,
fixing some edge cases. No new functionality was added in this
commit.

lib/requests/compat.py

@@ -1,10 +1,17 @@
 # -*- coding: utf-8 -*-
 
 """
-pythoncompat
+requests.compat
+~~~~~~~~~~~~~~~
+
+This module handles import compatibility issues between Python 2 and
+Python 3.
 """
 
-from .packages import chardet
+try:
+    import chardet
+except ImportError:
+    import charset_normalizer as chardet
 
 import sys
 
@@ -21,11 +28,11 @@ is_py2 = (_ver[0] == 2)
 #: Python 3.x?
 is_py3 = (_ver[0] == 3)
 
+has_simplejson = False
 try:
     import simplejson as json
-except (ImportError, SyntaxError):
-    # simplejson does not support Python 3.2, it throws a SyntaxError
-    # because of u'...' Unicode literals.
+    has_simplejson = True
+except ImportError:
     import json
 
 # ---------
@@ -33,30 +40,42 @@ except (ImportError, SyntaxError):
 # ---------
 
 if is_py2:
-    from urllib import quote, unquote, quote_plus, unquote_plus, urlencode, getproxies, proxy_bypass
+    from urllib import (
+        quote, unquote, quote_plus, unquote_plus, urlencode, getproxies,
+        proxy_bypass, proxy_bypass_environment, getproxies_environment)
     from urlparse import urlparse, urlunparse, urljoin, urlsplit, urldefrag
     from urllib2 import parse_http_list
     import cookielib
     from Cookie import Morsel
     from StringIO import StringIO
-    from .packages.urllib3.packages.ordered_dict import OrderedDict
+    # Keep OrderedDict for backwards compatibility.
+    from collections import Callable, Mapping, MutableMapping, OrderedDict
 
     builtin_str = str
     bytes = str
     str = unicode
     basestring = basestring
     numeric_types = (int, long, float)
+    integer_types = (int, long)
+    JSONDecodeError = ValueError
 
 elif is_py3:
     from urllib.parse import urlparse, urlunparse, urljoin, urlsplit, urlencode, quote, unquote, quote_plus, unquote_plus, urldefrag
-    from urllib.request import parse_http_list, getproxies, proxy_bypass
+    from urllib.request import parse_http_list, getproxies, proxy_bypass, proxy_bypass_environment, getproxies_environment
     from http import cookiejar as cookielib
     from http.cookies import Morsel
     from io import StringIO
+    # Keep OrderedDict for backwards compatibility.
     from collections import OrderedDict
+    from collections.abc import Callable, Mapping, MutableMapping
+    if has_simplejson:
+        from simplejson import JSONDecodeError
+    else:
+        from json import JSONDecodeError
 
     builtin_str = str
     str = str
     bytes = bytes
     basestring = (str, bytes)
     numeric_types = (int, float)
+    integer_types = (int,)