missing uglify-js, make browser fails on sed

## Expected
1. uglify-js should be a dev-dependency in npm `package.json`
2. `make browser` builds correctly
## Actual

Output as follows...

```
# super hacky build script for browser version!
# etc...
echo "nodeunit.run = reporter.run;" >> dist/browser/nodeunit.js
echo "return nodeunit; })();" >> dist/browser/nodeunit.js
sed -i "/\@REMOVE_LINE_FOR_BROWSER/d" dist/browser/nodeunit.js
sed: 1: "dist/browser/nodeunit.js": extra characters at the end of d command
make: *** [browser] Error 1
```

读取 npm package.json 和 make browser 目标，然后运行 make browser 以复现 sed 失败。完成的标准是将 uglify-js 声明为开发依赖项，并且浏览器构建在没有报告的错误的情况下完成。

由索引模型根据 Issue 内容生成。