Removed virtual methods from base class as this was breaking the casting. Ironically this fix was required as the original "fix" for issue raised by Coverity introduced

a crash!

src/osgPlugins/ive/ReadWrite.h

@@ -180,11 +180,7 @@ namespace ive {
 #define IVEFADETEXT                     0x10000003
 
 class ReadWrite{
-
 public:
-    virtual ~ReadWrite() {}
-    virtual void write(DataOutputStream* out) = 0;
-    virtual void read(DataInputStream* out) = 0;
 };
 
 }