Changeset 410 for trunk/upgrade.php

first version of an upgrade script.
This script will look for files in a directory
with the format: upgrades/<dbtype>/2.0to2.1.php
It will look in the settings database for the value of
dbversion and apply all patches that are newer.
The content of the files should be like:
<?php
$sql = array(

"sql query 1",
"sql query 2"

);
?>

There is no backingup of the current database and stuff.
We need to do that, so dont use this script yet.

Re #124