[python-asyncio] tests and fixes (#7235)

* fix: creating ssl context and passing args/files/forms

* feat: python-async add tests

* chore: rebuild petstore sample for python, tornado and asyncio

* feat: add python asyncio to travis

* feat: print coverage (python-asyncio)

samples/client/petstore/python-asyncio/test_python3.sh

@@ -0,0 +1,32 @@
+#!/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 --python python3
+		source $VENV/bin/activate
+    DEACTIVE=true
+fi
+
+### install dependencies
+pip install -r $REQUIREMENTS_FILE | tee -a $REQUIREMENTS_OUT
+python setup.py develop
+
+### run tests
+tox || exit 1
+
+### static analysis of code
+flake8 --show-source petstore_api/
+
+### deactivate virtualenv
+#if [ $DEACTIVE == true ]; then
+#    deactivate
+#fi