Fixed the test framework by adjusting it to mmh.

In the same go: Cleaned up its code a bit and added a summary to
test/runalltests.

Adjusting the individual tests to mmh still needs to be done. ... and
afterwards we can ;dd a lot more of them. :-) (But before we write our
own tests, we first incorporate all the ones they've added to nmh in
the meanwhile. ;-) )