Add multiple servers support to Python client (#1969)

* add multiple server support to python client

* various fixes

* minor fixes, add tests

* test oas2 python first

* fix tests

* fix issues reported by flake8

* update code format

* add python petstore to ensure up-to-date

* rearrange test

* fix E501

* fix tests

* add new files

* fix script permission

* fix index check

* update samples

samples/openapi3/client/petstore/python/test_python2.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+REQUIREMENTS_FILE=dev-requirements.txt
+REQUIREMENTS_OUT=dev-requirements.txt.log
+SETUP_OUT=*.egg-info
+VENV=.venv
+DEACTIVE=false
+
+export LC_ALL=en_US.UTF-8
+export LANG=en_US.UTF-8
+
+### set virtualenv
+if [ -z "$VIRTUAL_ENV" ]; then
+		virtualenv $VENV --no-site-packages --always-copy
+		source $VENV/bin/activate
+    DEACTIVE=true
+fi
+
+### install dependencies
+pip install -r $REQUIREMENTS_FILE | tee -a $REQUIREMENTS_OUT
+python setup.py develop
+
+### run tests
+nosetests || exit 1
+
+### static analysis of code
+flake8 --show-source petstore_api/
+
+### deactivate virtualenv
+#if [ $DEACTIVE == true ]; then
+#    deactivate
+#fi
+