Remove unnecessary extension of Token file

The file used to store the Google Calendar Authentication Token has been
renamed from GoogleCalAuthenticationToken.txt to
GoogleCalAuthenticatonToken.

Why is this change necessary?
- The file was never a text file. It was always a binary file. Removing
  the .txt helps remove any confusion which may be posed to the user, as
  the user is not supposed to open this file and edit its contents.
Merge branch 'wip/GCal'