Reusing the config file on install skips authorization

Your OS (including version) where you are running AlexaPi:

OSMC (Debian 8.7)

Your hardware platform and model you are running on:

Raspberry PI 2

Python release (python2 --version):

Python 2.7.9

Description of problem:

If you already have a config file the installer will ask if you want to Keep, Edit or Delete, choosing Keep it does exit the installer even if there is no token saved in the config file. You need to run manually python auth_web.py to finish the configuration.

Expected:

Check if there is a token and is not expired and only then skip the authorization part.

Problem-relevant config.yaml entries:

Steps to reproduce:

1. Install AlexaPi and kill or get an error after config is created but before authorization is saved
2. Try to install again

Traceback (if applicable):

Additional info: