Log at a more reasonable level

Currently, every single pixel that is being painted emits a log message in debug mode. Set it to trace instead!

src/main/java/org/janelia/saalfeldlab/paintera/control/assignment/FragmentSegmentAssignmentOnlyLocal.java

@@ -117,7 +117,7 @@ public synchronized long getSegment(final long fragmentId)
 		{
 			id = segmentId;
 		}
-		LOG.debug("Returning {} for fragment {}: ", id, fragmentId);
+		LOG.trace("Returning {} for fragment {}: ", id, fragmentId);
 		return id;
 	}