DataSpec/DNACommon: Resolve indirect includes where applicable

Avoids indirect inclusions where applicable and includes the necessary
headers as used by the interface. This way, it prevents code from
failing to compile due to changes in other header inclusions.

DataSpec/DNACommon/OBBTreeBuilder.hpp

@@ -1,6 +1,8 @@
 #pragma once
 
-#include "DNACommon.hpp"
+#include <memory>
+
+#include <hecl/Blender/Connection.hpp>
 
 namespace DataSpec {