Added the ability for osgParticle::ParticleEffect to switch off the automatic setup.

Normally the automatic setup is useful, but in the case of the .osg support this automatic
update was forcing premature loading of imagery that wasn't necessarily, and can lead to
reports of looking for files that arn't present.

include/osgParticle/ParticleEffect

@@ -24,7 +24,8 @@ namespace osgParticle
     {
     public:
     
-        ParticleEffect():
+        ParticleEffect(bool automaticSetup=true):
+            _automaticSetup(automaticSetup),
             _useLocalParticleSystem(true),
             _scale(1.0f),
             _intensity(1.0f),
@@ -41,6 +42,9 @@ namespace osgParticle
         virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const ParticleEffect*>(obj) != 0; }
         virtual void accept(osg::NodeVisitor& nv) { if (nv.validNodeMask(*this)) { nv.pushOntoNodePath(this); nv.apply(*this); nv.popFromNodePath(); } }
 
+        void setAutomaticSetup(bool flag) { _automaticSetup = flag; }
+        bool getAutomaticSetup() const { return _automaticSetup; }
+
         void setUseLocalParticleSystem(bool local);
         bool getUseLocalParticleSystem() const { return _useLocalParticleSystem; }
 
@@ -93,6 +97,8 @@ namespace osgParticle
     protected:
     
         virtual ~ParticleEffect() {}
+        
+        bool                            _automaticSetup;
 
         osg::ref_ptr<ParticleSystem>    _particleSystem;