Update migration, fix various minor issues

- Lot of people couldn't migrate to v1 and plan to reevaluate when v2 is
  released.
- It's "npm" not "NPM". It doesn't stand for anything, and it never
  has - it was initially chosen simply because it was easy to type.
  It has a lot of unofficial backronyms with "Node Package Manager"
  being one of the most common ones, but it's never officially stood
  for anything as an acronym *or* initialism.
- Fixed a few errors in the change log, like non-breaking changes being
  included in the "Breaking Changes" section and an inaccuracy in the
  summary of a particular change.
- Fixed RawGit URLs to point to GitHack, which is a lighter proxy that
  offloads caching to Cloudflare instead of also implementing it itself.
  (It also just uses nginx for all the important server logic, so it
  scales better.)
- Add a few more v0.2 references as appropriate

docs/credits.md

@@ -21,6 +21,6 @@ Special thanks to:
 
 Other people who also deserve recognition:
 
-- Arthur Clemens - creator of [Polythene](https://github.com/ArthurClemens/Polythene) and the [HTML-to-Mithril converter](http://arthurclemens.github.io/mithril-template-converter/index.html)
+- Arthur Clemens - creator of [Polythene](https://github.com/ArthurClemens/Polythene) and the [HTML-to-Mithril converter](https://arthurclemens.github.io/mithril-template-converter/index.html)
 - Stephan Hoyer - creator of [mithril-node-render](https://github.com/StephanHoyer/mithril-node-render), [mithril-query](https://github.com/StephanHoyer/mithril-query) and [mithril-source-hint](https://github.com/StephanHoyer/mithril-source-hint)
 - the countless people who have reported and fixed bugs, participated in discussions, and helped promote Mithril