Fix #4, Fix #5, add user registration date to db, prevent email collision, add functions for checking username and email existence
fix #8, add quotes around  in authenticateUser
fix bug of missing asterisks in existUser/Email
remove echo in users.php
add function for query user points

prevent duplicate (user,problem) in submissinos

add getSubmissionById

Fix #9
fix rand salt too large in linux
fix rand hash, add description attr
add projects and rankrewards

fix single quote bug in submission add
add deletion for projects and rankrewards
Merge pull request #7 from yubowenok/db

Fix #4, Fix #5, add user registration date to db, prevent email collisio...
Merge branch 'master' into webpage