[Python] Adds new client generator, python-experimental (#3244)

* Adds python-experimental generator

* Adds python-experimental samples folder which uses its own v2 spec

* Adds enusre-up-to-date updates

* Removes samples/client/petstore/perl/t/AnotherFakeApiTest.t

* Removes comment line from python-experimental generator

* Reverts perl docs file

* Updates perl sample client

* Adds python-experimental to pom.xml

* Copies the python test foldeers tests and testfiles into python-experimental

* Copies python test folder into python-experimental

* Moves python testing from Travis (samples pom.xml profile) to Circlci (samples.circleci pom.xml profile)

* Adds python-experimental pom.xml

* Adds python-experimental makefile and .sh files

* Chenges python-experimental to use gitignored venv rather than .venv which is not ignored when testing

* Adds dev-requiremnts.txt and removes .travis.yml from python-experimental so CI tests will pass

* Moves python-experimental from CicleCI to Travis to get support for multiple python environments

* Updates generator java comment so CI tests will run over again

samples/client/petstore/python-experimental/test/test_file.py

@@ -0,0 +1,39 @@
+# coding: utf-8
+
+"""
+    OpenAPI Petstore
+
+    This spec is mainly for testing Petstore server and contains fake endpoints, models. Please do not use this for any other purpose. Special characters: \" \\  # noqa: E501
+
+    OpenAPI spec version: 1.0.0
+    Generated by: https://openapi-generator.tech
+"""
+
+
+from __future__ import absolute_import
+
+import unittest
+
+import petstore_api
+from petstore_api.models.file import File  # noqa: E501
+from petstore_api.rest import ApiException
+
+
+class TestFile(unittest.TestCase):
+    """File unit test stubs"""
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def testFile(self):
+        """Test File"""
+        # FIXME: construct object with mandatory attributes with example values
+        # model = petstore_api.models.file.File()  # noqa: E501
+        pass
+
+
+if __name__ == '__main__':
+    unittest.main()