Added support for PagedLOD node into .ive format and added support for

Enabled texture object reuse by setting an expiry delay in the TextureObjectManager
of 10 seconds - done for both osgDB::DatabasePager and TXP plugin.

src/osgDB/DatabasePager.cpp

@@ -170,6 +170,10 @@ public:
 void DatabasePager::run()
 {
     std::cout<<"DatabasePager::run()"<<std::endl;
+
+    // need to set the texture object manager to be able to reuse textures
+    // by keeping deleted texture objects around for 10 seconds after being deleted.
+    osg::Texture::getTextureObjectManager()->setExpiryDelay(10.0f);
     
     while(true)
     {