Pylint doesn't take anymore the default rcfile if the rcfile specified on the command line doesn't exist (#1768)

Fixes ``pylint disable=fixme` directives ignored for comments following the last statement in a file (#1740)

Fixes #1681

Change log entry added in #1733 was accidentally removed in commit
996b3fb5 in PR #1726

Adding changelog entry back.

Fixes: #1301

Shallow copy of os.environ doesn't work as people may expect. os.environ
is not a dict object but rather a proxy object, so any changes made
on the copy may have unexpected effects on os.environ

Instead of copy.copy(os.environ) method os.environ.copy() should be
used.

Message id is: `shallow-copy-environ`

See https://bugs.python.org/issue15373 for details.

Resolves: #1301

* Extend trailing-comma-tuple check to more complex assignments

The previous implementation was too conservative with looking for
previous tokens associated with assignment: It looked only
at the immediately previous token, causing 'a = (5),' to not be
caught.

Now The current implementation backtracks to the start of the line
to find an assignment substring.

Fixes issue #1713

A method can reimplement a super method in order to provide a different default value, in which case we shouldn't emit ``useless-super-delegation``.

Closes #1420

Close #1673

Close #1267

Closes #1013

* Add of a new regexp for Keyword Args|Arguments|Parameters. Extending the list of entries in match_param_docs method with the results of self._parse_section(new_regexp)

* Add of 2 unittests for Google docstring with Args and Keyword Args.

* Add of ChangeLog and whatsnew entries

Adding a warning about keyword argument appearing before variable args list in the function definition (#1636)

Closes #574

A PR was merged that introduced a changelog entry in a previous release.

This PR places the entry in the correct (upcoming) release section.

Added ``suggestion-mode`` configuration flag. When flag is enabled, informational
message is emitted instead of cryptic error message for attributes accessed on
c-extensions.

Close #1466

Close #1176

simplify-boolean-expression is now emitted for old style ternaries with first value being falsy in boolean context (#1560)

Closes #1559

* parametrize count of suggestions based on config parameter
* fix tests on Appveyor

Close #1608

Close #1479

Added stop-iteration-return

Following the recommendations of PEP479 ,a new Python 3.0 checker was added
to warn about raising a StopIteration inside a generator. Raising a StopIteration
inside a generator may be due a direct call to `raise StopIteration`.

Close #1385

Added a couple of new Python 3 checks for accessing dict methods in non-iterable context. Part of #377

Protocol checks (not-a-mapping, not-an-iterable and co.) aren't emitted on classes with dynamic getattr. Close #1579

This message is emitted when the threading.Thread class does not
receive the target argument, but receives just one argument, which
is by default the group parameter.

Close #1327

Disabling 'ungrouped-imports' for a single line now prevents that line from triggering violations on subsequent lines.

Disabling 'wrong-import-order' or 'wrong-import-position' for a single line now prevents that line from triggering violations on subsequent lines.