Better/faster exporting

* add --build and --build-dir options to sapper export (#325)

* tweak export logging, update port-authority to prevent timeout bug

* better logging of export progress

* handle case where linked resource is already fetched

* default to .sapper/dev instead of .sapper

* handle query params and redirects

* dont write server_info.json either - second half of #318

* update changelog

* update lockfile

* try to track down ci test failures

* err wut

* curiouser and curiouser

* ok, seems to work now

src/api/utils/Deferred.ts

@@ -0,0 +1,12 @@
+export default class Deferred {
+	promise: Promise<any>;
+	fulfil: (value?: any) => void;
+	reject: (error: Error) => void;
+
+	constructor() {
+		this.promise = new Promise((fulfil, reject) => {
+			this.fulfil = fulfil;
+			this.reject = reject;
+		});
+	}
+}