Remove debug printf

Signed-off-by: Anton Lundin <glance@acc.umu.se>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
Enable Marble debug messages from Subsurface command line

Calling Subsurface with -v now gets you debug output. Of course, with a
regular "release" build of Marble you still won't see much. But with the
changes in the special Subsurface-testing branch you actually get some
very useful information when debugging a lack of maps in Marble.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>