covid19.analytics Version 2.1

More data sources added _ ver 2.1 (Feb/Mar 2021)
- Vaccination data, from OWID
- Testing data, from OWID
- pandemics data, from Visual Capitalist infographics
- adding flags for having conditional testing (in unit testing module)

Adding more data sources _ ver 2.01/unreleased/ (Oct 2020)
- New covid19.Toronto_OD.data fn, to obtain data from Open Data Toronto
- New covid19.Canada.data fn, to obtain data from Health Canada