Support Svelte 3

fixes #546, #551, #552, #554

test/apps/basics/src/routes/[slug].html

@@ -1 +1,5 @@
-<h1>{params.slug.toUpperCase()}</h1>
+<script>
+	import { page } from '@sapper/app';
+</script>
+
+<h1>{$page.params.slug.toUpperCase()}</h1>

test/apps/basics/src/routes/b/index.html

@@ -1,11 +1,13 @@
-<h1>{letter}</h1>
+<script context="module">
+	export function preload() {
+		return this.fetch('b.json').then(r => r.json()).then(letter => {
+			return { letter };
+		});
+	}
+</script>
 
 <script>
-	export default {
-		preload() {
-			return this.fetch('b.json').then(r => r.json()).then(letter => {
-				return { letter };
-			});
-		}
-	};
-</script>
+	export let letter;
+</script>
+
+<h1>{letter}</h1>

test/apps/basics/src/routes/delete-test/index.html

@@ -1,19 +1,17 @@
-<button class='del' on:click='del()'>delete</button>
-
 <script>
-	export default {
-		oncreate() {
-			window.deleted = null;
-		},
+	import { onMount } from 'svelte';
 
-		methods: {
-			del() {
-				fetch(`delete-test/42.json`, { method: 'DELETE' })
-					.then(r => r.json())
-					.then(data => {
-						window.deleted = data;
-					});
-			}
-		}
-	};
-</script>
+	onMount(() => {
+		window.deleted = null;
+	});
+
+	function del() {
+		fetch(`delete-test/42.json`, { method: 'DELETE' })
+			.then(r => r.json())
+			.then(data => {
+				window.deleted = data;
+			});
+	}
+</script>
+
+<button class="del" on:click={del}>delete</button>

test/apps/basics/src/routes/echo-query/index.html

@@ -1 +1,5 @@
-<h1>{JSON.stringify(query)}</h1>
+<script>
+	import { page } from '@sapper/app';
+</script>
+
+<h1>{JSON.stringify($page.query)}</h1>

test/apps/basics/src/routes/unsafe-replacement.html

@@ -1,9 +1,7 @@
-$&
+<script context="module">
+	export function preload() {
+		return '$&';
+	}
+</script>
 
-<script>
-	export default {
-		preload() {
-			return '$&';
-		}
-	};
-</script>
+$&