Merge branch 'dev'

* dev:
  v0.4.2
  fix serverity level colors
  Fix type cast in request.query.get webapp
Merge branch 'dev'

* dev:
  v0.4.3
  Update faq#analyzer-cluster, now it was built-in supported
  Add config items `workers` for analyzer & webapp
  Add built-in cluster support for webapp
  Add built-in cluster support for analyzer
  Patterns refresh interval changed to static number: 60 * 1e3 = 1min
Merge branch 'dev'

* dev:
  Add link in readme
  Add tutorial zh
  Fix comment typo {Patterns} => {Global}
Rename bin/cli.js to bin/bell.js