Changed MySQLWrapper to throw exception on connection error
Changed display_error_page function

Changed display_error_page function in error_handler.php to manually
load the error module if the second argument ($database_error) is set
to true
Added try catch block to index.php

Wrapper the instantiation of MySQLWrapper in a try catch block to catch
the mysqli_sql_exception and show an error page if it's caught
Added todo to errors module