Move the cli creation into the function so that potentially multiple CLIs with different configurations can be executed at the same time.
- hope it fixes #10
python3 -m venv env
pip install 'az.cli==0.5'
python3>>> from az.cli import az
>>> import os
>>> exit_code, result_dict, logs = az("group list")
>>> print (result_dict)
[{'id': '/subscriptions/...', 'location': 'westeurope', 'name': 'test1']
>>> os.environ['AZURE_CONFIG_DIR'] = '/Users/mark/.azure_mw'
>>> exit_code, result_dict, logs = az("group list")
>>> print (result_dict)
[{'id': '/subscriptions/...', 'location': 'westeurope', 'name': 'test2']