Deservicify core (#2458)

* De-servicify router (mostly)

Still uses the redraw service, but it no longer has an intermediate
service of its own.

Also, did a *lot* of test deduplication in this. About 30-40% of the
router service tests were already tested on the main router API instance
itself.

Bundle size decreased from 9560 to 9548 bytes min+gzip.

* Merge `m.mount` + `m.redraw`, update router

Simplifies the router and redraw mechanism, and makes it much easier to
keep predictable.

Bundle size down to 9433 bytes min+gzip, docs updated accordingly.

* Make `mithril/render` just return the `m.render` function directly.

* Deservicify `m.render`, revise `m.route`

- You now have to use `mithril/render/render` directly if you want an
  implicit redraw function. (This will likely be going away in v3.)
- Revise `m.route` to only `key` components

* Add `redraw` to `m.render`, deservicify requests

* Test error logging

* Update docs + changelog [skip ci]

docs/hyperscript.md

@@ -454,7 +454,7 @@ var isError = false
 m("div", isError ? "An error occurred" : "Saved") // <div>Saved</div>
 ```
 
-You cannot use JavaScript statements such as `if` or `for` within JavaScript expressions. It's preferable to avoid using those statements altogether and instead, use the constructs above exclusively in order to keep the structure of the templates linear and declarative, and to avoid deoptimizations.
+You cannot use JavaScript statements such as `if` or `for` within JavaScript expressions. It's preferable to avoid using those statements altogether and instead, use the constructs above exclusively in order to keep the structure of the templates linear and declarative.
 
 ---