Please note that this commit only uses the @Test annotation
where exceptions are thrown at the end of the test,
because otherwise the test would not be executed completely.

Examples for this are in DatabaseComponentImplTest where many exceptions
are thrown in close succession or in ConnectionRegistryImplTest where an
exception is thrown in the middle of the test.

This breaks backward compatibility for the wire protocol and messages
stored in the database. The database schema version has been
incremented.

This adds complexity but will save a lot of bandwidth, as most of the
strings and byte arrays we want to send are less than 128 bytes.

The extra complexity isn't exposed outside of the serial component.

The new format is simpler but less efficient for small integers, short
strings and short byte arrays.