Add task 4 about debugging
Try different diffing highlighting
Fix image
Fix nested listing
Finish task4
Emphasize the dollar prefix
Add instructions to enter directory before doing npm install
Add explanation about using local data file
Add tip to install jshint globally
Merge branch 'master' of https://github.com/CMDA/sss-exercises

* 'master' of https://github.com/CMDA/sss-exercises:
  Add tip to install jshint globally
  Add explanation about using local data file
  Add instructions to enter directory before doing npm install
  Emphasize the dollar prefix
  Finish task4
  Fix nested listing
  Fix image
  Try different diffing highlighting
  Add task 4 about debugging