Mathias Fr�hlich:

Incorporating the shared ptr code:
- All scenegraph references from SimGear
- SGMaterial which already had a reference counter uses now that common
  infrastructure.
- SGMatModel is now counted.
- SGSoundSample from SimGear
- And the corresponding change for the sound samples in flightgear which fixes
  a latent crash if FGBeacon would evern be deleted.

src/Sound/beacon.cxx

@@ -25,18 +25,12 @@
 
 
 // constructor
-FGBeacon::FGBeacon() :
+FGBeacon::FGBeacon()
-    inner(NULL),
-    middle(NULL),
-    outer(NULL)
 {
 }
 
 // destructor
 FGBeacon::~FGBeacon() {
-    delete inner;
-    delete middle;
-    delete outer;
 }
 
 

src/Sound/beacon.hxx

@@ -32,6 +32,8 @@
 
 #include <simgear/compiler.h>
 #include <simgear/sound/soundmgr_openal.hxx>
+#include <simgear/structure/SGReferenced.hxx>
+#include <simgear/structure/SGSharedPtr.hxx>
 
 #include "morse.hxx"
 
@@ -93,9 +95,9 @@ class FGBeacon {
 
 private:
 
-    SGSoundSample *inner;
+    SGSharedPtr<SGSoundSample> inner;
-    SGSoundSample *middle;
+    SGSharedPtr<SGSoundSample> middle;
-    SGSoundSample *outer;
+    SGSharedPtr<SGSoundSample> outer;
 
 public: