Feat/2.1.0 release changelog documentation (#466)

* chore(changelog): add changelog for 2.1.0 release

* doc(rewind): add documentation a new feature `rewind` that can replay a cassette

* doc(exception): add documentation on the new behavior of the CannotOverwriteExistingCassetteException message

docs/advanced.rst

@@ -372,3 +372,16 @@ cassette names, use ``VCR.ensure_suffix`` as follows:
 
     @my_vcr.use_cassette
     def my_test_function():
+
+Rewind Cassette
+---------------
+
+VCR.py allows to rewind a cassette in order to replay it inside the same function/test.
+
+.. code:: python
+
+    with vcr.use_cassette('fixtures/vcr_cassettes/synopsis.yaml') as cass:
+        response = urllib2.urlopen('http://www.zombo.com/').read()
+        assert cass.all_played
+        a.rewind()
+        assert not cass.all_played

docs/changelog.rst

@@ -1,7 +1,17 @@
 Changelog
 ---------
--  2.0.2 (UNRELEASED) - Drop support to python 3.4
+-  2.1.1 (UNRELEASED)
+-  2.1.0 - Add a `rewind` method to reset a cassette (thanks @khamidou)
+   New error message with more details on why the cassette failed to play a request (thanks @arthurHamon2, @neozenith)
+   Handle connect tunnel URI (thanks @jeking3)
+   Add code coverage to the project (thanks @neozenith)
+   Drop support to python 3.4
+   Add deprecation warning on python 2.7, next major release will drop python 2.7 support
    Fix build problems on requests tests (thanks to @dunossauro)
+   Fix matching on 'body' failing when Unicode symbols are present in them (thanks @valgur)
+   Fix bugs on aiohttp integration (thanks @graingert, @steinnes, @stj, @lamenezes, @lmazuel)
+   Fix Biopython incompatibility (thanks @rishab121)
+   Fix Boto3 integration (thanks @1oglop1, @arthurHamon2)
 -  2.0.1 - Fix bug when using vcrpy with python 3.4
 -  2.0.0 - Support python 3.7 (fix httplib2 and urllib2, thanks @felixonmars)
    [#356] Fixes `before_record_response` so the original response isn't changed (thanks @kgraves)

docs/debugging.rst

@@ -29,3 +29,29 @@ The second time, you will see::
 If you set the loglevel to DEBUG, you will also get information about
 which matchers didn't match. This can help you with debugging custom
 matchers.
+
+CannotOverwriteExistingCassetteException
+========================================
+
+When a request failed to be found in an existing cassette,
+VCR.py tries to get the request(s) that may be similar to the one being searched.
+The goal is to see which matcher(s) failed and understand what part of the failed request may have changed.
+It can return multiple similar requests with :
+
+- the matchers that have succeeded
+- the matchers that have failed
+- for each failed matchers, why it has failed with an assertion message
+
+CannotOverwriteExistingCassetteException message example :
+
+.. code:: python
+
+    CannotOverwriteExistingCassetteException: Can't overwrite existing cassette ('cassette.yaml') in your current record mode ('once').
+    No match for the request (<Request (GET) https://www.googleapis.com/?alt=json&maxResults=200>) was found.
+    Found 1 similar requests with 1 different matchers :
+
+    1 - (<Request (GET) https://www.googleapis.com/?alt=json&maxResults=500>).
+    Matchers succeeded : ['method', 'scheme', 'host', 'port', 'path']
+    Matchers failed :
+    query - assertion failure :
+    [('alt', 'json'), ('maxResults', '200')] != [('alt', 'json'), ('maxResults', '500')]