First 'pseudo' SQL commands

Support for two new SQL statements: COMMIT and ROLLBACK. But this commands will not be sent to the database, instead the method Connection.commit() / Connection.rollback() is called. This is a first step towards more complex pseudo commands like Java 'stored procedures'.

Autocommit problems fixed (Oracle and PointBase have problems).

Added SQL grammar support for aggregates: MIN, MAX, AVG, SUM, COUNT.

Added support for IN(value, value,...)

The BLOB/CLOB limitation on MySQL is now around 400'000 instead of 65'000.