Slot-based routing (#573)

test/apps/preloading/src/routes/_layout.svelte

@@ -8,13 +8,16 @@
 
 <script>
 	import { preloading } from '@sapper/app';
+	import { setContext } from 'svelte';
 
 	export let child;
 	export let rootPreloadFunctionRan;
+
+	setContext('x', { rootPreloadFunctionRan });
 </script>
 
 {#if $preloading}
 	<progress class='preloading-progress' value=0.5/>
 {/if}
 
-<svelte:component this={child.component} {rootPreloadFunctionRan} {...child.props}/>
+<slot></slot>

test/apps/preloading/src/routes/prefetch/_layout.html

@@ -1 +0,0 @@
-<svelte:component this={child.component} {...child.props}/>

test/apps/preloading/src/routes/preload-root/index.html

@@ -1 +0,0 @@
-<h1>root preload function ran: {rootPreloadFunctionRan}</h1>

test/apps/preloading/src/routes/preload-root/index.svelte

@@ -0,0 +1,6 @@
+<script>
+	import { getContext } from 'svelte';
+	const { rootPreloadFunctionRan } = getContext('x');
+</script>
+
+<h1>root preload function ran: {rootPreloadFunctionRan}</h1>

test/apps/preloading/src/routes/preload-values/index.html

@@ -1 +0,0 @@
-<svelte:component this={child.component} {...child.props}/>