Implementation of prefix in tables; phase one:

---------------  Modifying installation scripts  ---------------

a).-     It has split the charge script of DB into two parts,  basicdata.sql and structure.sql.
b).-     In config_sample.php has been included constants names of tables and the prefix variable
c).-     Writeconfig.php has been modified to display the menu option to enter the prefix
d).-     A database.php has been added two new functions and deleted the controller mysql, implementing mysqli controller, for best compatibility with other OS.