Added feature to delete users in admin.php
Cleaned up error messages in apache log
Added mysql security to login.php and add_user.php.
Added admin log to admin tab with scripts/admin.php, scripts/js/admin_page.js,
and scritps/style/admin.css by johnburd <johnburd19@gmail.com>.
Renamed README to README.md for markdown
Updated README.md with Markdown
Added function to see if user exists in add_user.php.