add option <port> to command `start`, `serve`
remove testing line
typofixes
update Readme and changes
typofix
watch help
update docs
add pdf link to index doc
Merge branch 'dev'

* dev:
  add pdf link to index doc
  update docs
  watch help
  typofix
  update Readme and changes
  typofixes
  remove testing line
  add option <port> to command `start`, `serve`