add comment functionality to editor
Merge branch 'master' of https://github.com/seanxiaoxiao/cmu_hackathon

* 'master' of https://github.com/seanxiaoxiao/cmu_hackathon:
  Fix bugs
  drawing change
  Canvas images
  Attrs
  to be fix
  Page layout
  Fix fomatting
  Firebase data
  draw array , circle and rectangle