Added expres endpoints in backend.js
Removed an unused endpoint on backend.js
Fixed a backend generator bug when retrieving prices in JSON format
Created initial version of frontend, using underscorejs on backend
Added last update time on panel. Preserved original display order of currencies
Added error message when the page can't update. Fixed update time display not displaying leading zeroes
Some arrangements for small devices
Added README file
Responded the last part of QnA.md
Fixed some typos on answers of QnA