BREAKING CHANGE:
- Default export removed. Use `import { marked } from 'marked'` or `const { marked } = require('marked')` instead.
- `/lib/marked.js` removed. Use `/marked.min.js` in script tag instead.
- When using marked in a script tag use `marked.parse(...)` instead of `marked(...)`
2. remove discount benchmark // not working on v0.8.x
3. add robotskirt benchmark
4. add target of bench in Makefile
5. add devDependencies in package.json
