MeshTools: include only what's strictly necessary in public headers.

There could eventually be a 2D variant, making Vector3 not needed, people
who don't need the AABB won't need the Range include, etc.

src/Magnum/MeshTools/BoundingVolume.cpp

@@ -26,8 +26,11 @@
 
 #include "BoundingVolume.h"
 
+#include <Corrade/Containers/Pair.h>
 #include <Corrade/Containers/StridedArrayView.h>
 
+#include "Magnum/Math/Range.h"
+#include "Magnum/Math/Vector3.h"
 #include "Magnum/Math/FunctionsBatch.h"
 
 namespace Magnum { namespace MeshTools {

src/Magnum/MeshTools/BoundingVolume.h

@@ -31,11 +31,7 @@
  * @m_since_latest
  */
 
-#include <Corrade/Containers/Pair.h>
-
 #include "Magnum/Magnum.h"
-#include "Magnum/Math/Range.h"
-#include "Magnum/Math/Vector3.h"
 #include "Magnum/MeshTools/visibility.h"
 
 namespace Magnum { namespace MeshTools {

src/Magnum/MeshTools/Test/BoundingVolumeTest.cpp

@@ -25,6 +25,7 @@
 */
 
 #include <Corrade/Containers/Array.h>
+#include <Corrade/Containers/Pair.h>
 #include <Corrade/Containers/StridedArrayView.h>
 #include <Corrade/TestSuite/Tester.h>
 #include <Corrade/TestSuite/Compare/Numeric.h>
@@ -32,6 +33,7 @@
 #include "Magnum/Math/FunctionsBatch.h"
 #include "Magnum/Math/TypeTraits.h"
 #include "Magnum/Math/Angle.h"
+#include "Magnum/Math/Range.h"
 #include "Magnum/Math/Vector3.h"
 #include "Magnum/MeshTools/BoundingVolume.h"
 #include "Magnum/MeshTools/Reference.h"