Copy of latest Google Calendar Backup program

Original at <https://github.com/LDavRoe/Google-Calendar-Backup>.
Use local naming convention
`pep8`-compatible script
Retire pre-2-factor-auth Google Calendar script
Unused and probably non-working scripts
Refactor for parameter use and `pep8` compliance

* __doc__ string
* Parameters instead of hardcoded credentials
* Split into functions