Partially recast the router API to be a lot more intuitive. (#2469)

* Recast the router API to be a lot more intuitive.

Fixes #2387
Fixes #2072
Fixes quite a few issues reported on Gitter.

For `m.route.Link`:

- More intuitive
- More accessible
- More ergonomic
- It can be disabled
- It can be cancelled
- It can be changed
- Oh, and you can use it isomorphically.

For `m.route.prefix`

- You can *read* it.
- You can write to it, of course.
- It's literally just setting a property.

For the router itself (and the rest of Mithril):

- You can now `require("mithril")` and all its submodules without a DOM
  at all. There is a catch: you can't instantiate any routes, you can't
  mount anything, and you can't invoke `m.render` in any capacity. You
  can only use `m.route.Link`, `m.route.prefix`, hyperscript stuff, and
  `mithril/stream`, and you can use `m.request` with `background: true`
  if you use a global XHR polyfill. (You can't use `m.request` without
  `background: true` except with a DOM to redraw with.) The goal here is
  to try to get out of the way for simple testing and to defer the
  inevitable `TypeError`s for the relevant DOM methods to runtime.

  The factory requires no arguments, and in terms of globals, you can
  just figure out based on what errors are thrown what globals to
  define. Their values don't matter - they just need to be set to
  *something*, even if it's just `null` or `undefined`, before Mithril
  executes.

Had to make quite a few other changes throughout the docs and tests to
update them accordingly. Oh, and that massive router overhaul enabled me
to do all this.

Also, slip in a few drive-by fixes to the mocks so they're a little
easier to work with and can accept more URLs. This was required for a
few of the tests.

* Update changelog + numbers, add forgotten bundle option

* Add PR numbers to changelog [skip ci]

* Allow continuing to the next match by returning `false`.

* Update numbers again

docs/simple-application.md

@@ -447,13 +447,16 @@ module.exports = {
 	oninit: User.loadList,
 	view: function() {
 		return m(".user-list", User.list.map(function(user) {
-			return m("a.user-list-item", {href: "/edit/" + user.id, oncreate: m.route.link}, user.firstName + " " + user.lastName)
+			return m(m.route.Link, {
+				class: "user-list-item",
+				href: "/edit/" + user.id,
+			}, user.firstName + " " + user.lastName)
 		}))
 	}
 }
 ```
 
-Here we changed `.user-list-item` to `a.user-list-item`. We added an `href` that references the route we want, and finally we added `oncreate: m.route.link`. This makes the link behave like a routed link (as opposed to merely behaving like a regular link). What this means is that clicking the link would change the part of URL that comes after the hashbang `#!` (thus changing the route without unloading the current HTML page)
+Here we swapped out the `.user-list-item` vnode with an `m.route.Link` with that class and the same children. We added an `href` that references the route we want. What this means is that clicking the link would change the part of URL that comes after the hashbang `#!` (thus changing the route without unloading the current HTML page). Behind the scenes, it uses an `<a>` to implement the link, and it all just works.
 
 If you refresh the page in the browser, you should now be able to click on a person and be taken to a form. You should also be able to press the back button in the browser to go back from the form to the list of people.
 
@@ -555,7 +558,7 @@ module.exports = {
 	view: function(vnode) {
 		return m("main.layout", [
 			m("nav.menu", [
-				m("a[href='/list']", {oncreate: m.route.link}, "Users")
+				m(m.route.Link, {href: "/list"}, "Users")
 			]),
 			m("section", vnode.children)
 		])
@@ -563,7 +566,7 @@ module.exports = {
 }
 ```
 
-This component is fairly straightforward, it has a `<nav>` with a link to the list of users. Similar to what we did to the `/edit` links, this link uses `m.route.link` to activate routing behavior in the link.
+This component is fairly straightforward, it has a `<nav>` with a link to the list of users. Similar to what we did to the `/edit` links, this link uses `m.route.Link` to create a routable link.
 
 Notice there's also a `<section>` element with `vnode.children` as children. `vnode` is a reference to the vnode that represents an instance of the Layout component (i.e. the vnode returned by a `m(Layout)` call). Therefore, `vnode.children` refer to any children of that vnode.