datatypes.tests needs __init__.py to be a module

Signed-off-by: martin f. krafft <madduck@madduck.net>
Purge mergers hierarchy

The rewrite of all the datatypes made the mergers unnecessary, i.e. they
are now integrated with the datatypes.

Signed-off-by: martin f. krafft <madduck@madduck.net>