Removed test mo-basic-240

As per issue #53
(https://github.com/mgylling/epub-testsuite/issues/53)
Changed authored MO highlight style to pink

It was yellow, but this is very common as a RS default, so it’s better
to pick something unusual for the purposes of testing.

This was mentioned in comments for issue #53
(https://github.com/mgylling/epub-testsuite/issues/53)