Some wamr-ide improvements (#1354)

including:
- enable macOS support
- documentation improvements
- fix some warnings

test-tools/wamr-ide/WASM-Toolchain/Docker/README.md

@@ -3,7 +3,6 @@
 -   Linux
 
     ```shell
-    chmod +x resource/*
     ./build_docker_image.sh
     ```
 
@@ -16,4 +15,4 @@
 ### Resource Details
 
 -   `Dockerflie` is the source file to build `wasm-debug-server` docker image.
--   `resource/build_wasm.sh` is the script to compile the wasm app with `wasi-sdk`.
+-   `resource/build_wasm.sh` is the script to compile the wasm app with `wasi-sdk`.

test-tools/wamr-ide/WASM-Toolchain/Docker/build_docker_image.bat

@@ -3,9 +3,6 @@
 
 @echo off
 
-@REM pull gcc and ubuntu image firstly no matter whether exist or not.
-docker pull gcc:9.3.0
-docker pull ubuntu:20.04
 docker build -t wasm-toolchain:1.0 .
 
 @REM delete intermediate docker image

test-tools/wamr-ide/WASM-Toolchain/Docker/build_docker_image.sh

@@ -1,9 +1,8 @@
+#!/bin/bash
+
 # Copyright (C) 2019 Intel Corporation.  All rights reserved.
 # SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 
-#!/bin/bash
-docker pull gcc:9.3.0
-docker pull ubuntu:20.04
 docker build -t wasm-toolchain:1.0 .
 
 # delete intermediate docker image