* DEFAULT value unquoting is done with preg_replace now (clearer that we want to do a string replacement)
* DEFAULT value unquoting works even if DEFAULT is not the last keyword
* change test datasource for more readability (use double quotes when needed)
* case insensitive SQL data type comparison
* some options have also case differences (example 'int(11) unsigned')
* DEFAULT 'NULL' added by MariaDB on all nullable fields
* default values are always surrounded with single quotes on MariaDB
This is a Combodo implementation of PR #91