If a github token is not provided or is malformed the tool will panic

[mattyjones]

Describe the bug
If the github token is malformed, is not provided, or is not authorized then the tool will panic with an unrelated error message. Turning on the debugging will show the user that they have gotten a 401 response. This should be fixed to either require a token and if not provided fail fast with an apprioate message or simply give a message describing the problem and how to fix it.

To Reproduce
Steps to reproduce the behavior:
Run the tool with no token or a bad token

Expected behavior
The tool should give an error message saying either the token was not found or the token was not valid

Desktop (please complete the following information):

• OS: Kali, Windows 10, OSX
• Version: 2.0.0-beta

Additional context
N/A

[mattyjones]

#42 fixes this