Merge branch 'proxyscheme' of git://github.com/Lukasa/requests into 2.0

diff --cc requests/utils.py
index e592c8b,618a5a1..347f2be
--- 1/requests/utils.py
--- 2/requests/utils.py
+++ b/requests/utils.py
@@@ -21,10 -21,11 +21,11 @@@ from netrc import netrc, NetrcParseErro
  from . import __version__
  from . import certs
  from .compat import parse_http_list as _parse_list_header
 -from .compat import quote, urlparse, bytes, str, OrderedDict, urlunparse
 -from .compat import getproxies, proxy_bypass
 +from .compat import (quote, urlparse, bytes, str, OrderedDict, urlunparse,
 +                     is_py2, is_py3, builtin_str, getproxies, proxy_bypass)
  from .cookies import RequestsCookieJar, cookiejar_from_dict
  from .structures import CaseInsensitiveDict
+ from .exceptions import MissingSchema
  
  _hush_pyflakes = (RequestsCookieJar,)