docs: Document release process & reformat .travis.yml (#1541)

* style: re-format travis config for readability

* docs: document npm release process

Still needs GitHub release/change-log steps (I've never done it though)

docs/releasing.md

@@ -0,0 +1,34 @@
+# Releasing
+
+Releasing new builds of mithril is mostly automated via `npm version`
+
+## Publishing to NPM
+
+1. `npm version <major|minor|patch|semver> -m "v%s"`
+
+All further steps are automated and run as follows:
+
+2. Tests are run
+3. Linting is run (but doesn't fail build)
+4. Version number in package.json is incremented
+5. New bundles are generated using updated version
+6. `git add` called on bundle output
+7. `package.json` and updated bundles are committed to git
+8. previous commit is tagged using new version number
+9. `git push --follow-tags` pushes up new version commit & tag to github
+10. Travis sees new release, starts build
+11. Travis generates new bundles before running tests
+12. Travis runs tests
+13. Travis lints files (but can't fail build)
+14. If build fails, abort
+15. Build succeeded, so travis will commit back any changes to the repo (but there won't be any)
+16. Travis sees that this commit has a tag associated with it
+17. Travis will use the encrypted npm creds in `.travis.yml` to publish a new version to npm
+
+## Publishing a GitHub release
+
+**TODO**
+
+## Updating `docs/change-log.md`
+
+**TODO**