Moved JS to /js, added jQuery, improved friends.php

At friends.php, added $con->error descriptions, fetch_array in OOP
style, removed <output>
There is a weird behavior at friends.js where
alert() confuses 'return false'
Confirm deleteq, simplify printQ at loadquestions

Closes #14
At printDate, a <time> element is produced
Also added some security headers at .htaccess