Fixed memory leaks in reference GBSA code

platforms/reference/src/gbsa/CpuImplicitSolvent.h

@@ -152,7 +152,7 @@ class CpuImplicitSolvent {
       
          --------------------------------------------------------------------------------------- */
 
-      ~CpuImplicitSolvent( );
+      virtual ~CpuImplicitSolvent( );
 
       // override of new/delete -- used when run in PS3 framework(?)
 

platforms/reference/src/gbsa/ImplicitSolventParameters.h

@@ -120,7 +120,7 @@ class ImplicitSolventParameters {
       
          --------------------------------------------------------------------------------------- */
     
-       ~ImplicitSolventParameters( );
+       virtual ~ImplicitSolventParameters( );
 
       // override of new/delete