Installer support for 'sqlite' or 'pgsql'.

[Austin Saint Aubin]

Have recommendation for updating ( sf_web_dir/pre_installer_code.php ).

I added support to install on system that is using 'sqlite' or 'pgsql'.

Have tested on my Synology NAS that only has 'sqlite' and 'pgsql' PDO drive.

ORIGNAL CODE:

  // PDO mysql driver
  $wrong['pdo_mysql'] = !in_array('mysql', array_map(
                                                     'strtolower',
                                                     PDO::getAvailableDrivers()
                                                     ));

UPDATED CODE:

  // PDO mysql driver
  $wrong['pdo_mysql'] = true;
  foreach (array('mysql', 'sqlite', 'pgsql') as $pdo_needle) {
    if ( in_array($pdo_needle, array_map('strtolower', PDO::getAvailableDrivers())) ) {
      $wrong['pdo_mysql'] = false;
    }
  }