v3.0.1

Bugfix release

This release fixes a few issues related to refreshing tokens.

Firstly, it fixes a misunderstanding in the README about how long refresh tokens last before they expire. The README stated that this is 200 days, when actually it's, more often than not, 7. I'd read the wrong part of the Google Documentation, and Google highlighting 200 days really didn't help that, sozza.

I've also fixed a bug where analytix couldn't handle refresh tokens being invalid -- you will now simply be prompted to manually reauthorise when necessary.