Bundle size and v2

[ricokahler]

Right now on bundlephobia, oauth2-popup-flow has a bundle size of 1.6kB. This is okay but it could be much smaller. I attribute this to the use of the classes and static methods that a minifier doesn't have the ability to minifiy.

For v2, we'll remove the class and that will probably give us a much smaller bundle size.

[ricokahler]

Eh i tried this out here: #24

this was the result: https://bundlephobia.com/result?p=@ricokahler/oauth2-popup-flow@2.0.0-alpha.1 vs https://bundlephobia.com/result?p=oauth2-popup-flow@1.1.0

removing the class did help the minified size significantly but the gzip is still the same so I don't think this change is worth it.