Added database structure

Closes #27
No alert for unsaved changes on form submit

At friends.js do not warn users for unsaved changes when they try to save
Also removed old useless variable 'submit'
This version still has a bug which was fixed in 63c1c290c53f9bfa7c91d6bd455380636e6941b1
POST to delete question

Closes #23
Modified search query structure

We SELECT FROM questions, users
questions.touser = users.username (instead of IN)
Hopefully it is faster (I think I read IN is slower)
Minor intendation at index.php
ToS: Add disclaimer for site's functionality
Merge master to semantic

At db changed users.textcolor to headcolor