Setup basic error report mechanism

Using a form to send error report written by users

lib/route.js: Add some lines to retrieve the content of post method.
mod/errreport.js: send email through nodemailer
tpl/errreport.ejs: nothing inside, just to fit the architecture
tpl/header.ejs: basic form to call ErrReportCtrl (in pub/js/index.js)
pub/js/index.js: ErrReportCtrl: Send form request to server to send
errreport
I missed one file in the last commit...more descriptions in the last commit