[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

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientExperimentalCodegen.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2018 OpenAPI-Generator Contributors (https://openapi-generator.tech)
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.openapitools.codegen.languages;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class PythonClientExperimentalCodegen extends PythonClientCodegen {
+    private static final Logger LOGGER = LoggerFactory.getLogger(PythonClientExperimentalCodegen.class);
+
+    public PythonClientExperimentalCodegen() {
+        super();
+    }
+
+    /**
+     * Configures a friendly name for the generator.  This will be used by the
+     * generator to select the library with the -g flag.
+     *
+     * @return the friendly name for the generator
+     */
+    @Override
+    public String getName() {
+        return "python-experimental";
+    }
+}