Thread method isAlive compatible with python 3.9

[dmknght]

• Faraday GTK Client version: 1.1.0
• Python version: 3.9
• Operating System: Parrot OS 4.10

Description

On Debian testing based distro, thee default python has been upgraded to python3.9 which removed isAlive(). It makes application failed to stop (crashes after click on exit)

What I Did

• Start Faraday-client
• Stop faraday client
• Client has this error while stopping

  Original exception was:
  Traceback (most recent call last):
  File "/usr/bin/faraday-client", line 11, in <module>
  load_entry_point('faraday-client==1.0.0', 'console_scripts', 'faraday-client')()
  File "/usr/lib/python3/dist-packages/faraday_client/start_client.py", line 448, in main
  start_faraday_client()
  File "/usr/lib/python3/dist-packages/faraday_client/start_client.py", line 227, in start_faraday_client
  exit_status = start()
  File "/usr/lib/python3/dist-packages/faraday_client/model/application.py", line 129, in start
  return self.__exit(exit_code)
  File "/usr/lib/python3/dist-packages/faraday_client/model/application.py", line 141, in __exit
  if self._model_controller.isAlive():
  TypeError: 'NoneType' object is not callable

  Link: https://bugs.python.org/issue37804

Fix method is edit isAlive() to is_alive() at https://github.com/infobyte/faraday-client/blob/master/faraday_client/model/application.py#L141 It worked well with python3.9. It should be compatible with python2 (doc: https://docs.python.org/2.7/library/threading.html) and any older version of python3 (doc: https://docs.python.org/3.5/library/threading.html)