Follow Tutorial 3 guidelines, add in remark command, test it and ensure unit tests are working, implement some features.

…ial-adding-command

* 'master' of https://github.com/Maurice2n97/tp:
  Format AboutUs to reflect Yi Qun's github and portfolio on one line.
  Change the image file name to lower case
  Change the image file name
  Change AboutUs image file name
  Update image and github link for Yi Qun.
  Update AboutUs
  Add my info and pic to aboutus
  ChenYuheng Finish AboutUs.md
  Change readme
  Change readme
  Update readme
  Change version for myself
  Set up the jekyll doc

add newline to RemarkCommandTest.java to ensure it pass CI