the rename solution is brilliant, but not sure how good idea it is to have test.html test absolutely everything

I really like test.migration.js, but wondering how we can make it more reusable, have it define the process of initialising an old pouch with data, then opening it with the current one and doing a set of common smoke tests on it to make sure the data is ok, pretty much as you have done but make the old pouch version parameratisable

Its possible we dont call it PouchDBVersion110 but just export it as `oldPouch`, we can then just load 1.1, 1.2 etc and run the same script?

I do think since these are such a different type of test that they shouldnt go in test.html, test-migrations.html and they can be added to test-browser.js?