Revert "Proxy urls should have explicit schemes."

This reverts commit 840540b6b1f07ef87faab73392c03fbef0dcc9fe.

Conflicts:
	requests/adapters.py
	requests/utils.py
Default proxy scheme to http.
Add documentation about decode_unicode.
Always honor decode_unicode, even when _content is present.

--HG--
extra : amend_source : 25977a1227b163d49bf2e1aec6aa448e5cd3be8a
Add tests for decode_unicode
Fix #1960: A Response's history should be a list
Fix #1955: Do not use original request in redirect

The original request was never being properly overriden in resolve_redirects.
As such being having a POST request respond with a 303 would generate a GET
request. If the GET request encountered another redirect to something like a
307, then it would use the original request and generate another POST request.

There are two parts to this fix:

- The fix itself
- The test infrastructure to ensure it does not regress because HTTPBin is
  insufficient
Actually assign history
Add __str__ to case insensitive dict. Logging headers for debugging purposes is often necessary, and the currently logging the headers would be using __repr__ which would log the implementation detail of headers, caseinsensitivedict. Adding str lends a more printing and log friendly implementation for case insentitice dict
Fix parenthesis typo
Shorten str for case insensitive dict
3.4
Merge remote-tracking branch 'origin/master'
Merge pull request #1963 from sigmavirus24/fix-redirect-methods

Fix #1955: Do not use original request in redirect
Merge pull request #1962 from sigmavirus24/fix-history-type

Fix #1960: A Response's history should be a list
The expected value changes for the proxies keyword

It used to be None but a recent PR changed that before my last one was merged
Merge pull request #1976 from kennethreitz/fix-redirect-test

The expected value changed for the proxies keyword
support request tuple data

rewrite the TestModels

Ajust the code
Update urllib to 1.8 (8a8c601bee)
Merge pull request #1981 from stanhu/master

Update urllib to 1.8 (8a8c601bee)