support app framework base library in assemblyscript (#164)

assembly-script/wamr_app_lib/console.ts

@@ -0,0 +1,15 @@
+/*
+ * Copyright (C) 2019 Intel Corporation.  All rights reserved.
+ * SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+ */
+
+@external("env", "printf")
+declare function printf(a: ArrayBuffer): i32;
+
+export function log(a: string): void {
+    printf(String.UTF8.encode(a + '\n', true));
+}
+
+export function log_number(a: number): void {
+    printf(String.UTF8.encode(a.toString() + '\n'));
+}