Fix assets and employees view

- modify app/scripts/templates/asset-details.ejs
- modify app/scripts/templates/assets.ejs
- modify app/scripts/templates/employee-details.ejs
- modify app/styles/main.scss
Fix edit / update module

- modify app/scripts/templates/employee-edit.ejs
  - add error message
- modify app/scripts/views/EmployeeView.js
  - add code to check error response
Fix employee-details edit/update module