Favor pointers over references

The use of a pointer instead of a reference conveys the message that the
lifetime of the object being pointed can, and most likely will, exceed the
lifetime of the function.

Also shuffled the member variables and internal functions around and
removed unneeded function declarations.

server/modules/routing/schemarouter/schemarouterinstance.cc

@@ -187,7 +187,7 @@ SchemaRouter* SchemaRouter::create(SERVICE* pService, char** pzOptions)
 
 SchemaRouterSession* SchemaRouter::newSession(MXS_SESSION* pSession)
 {
-    return new SchemaRouterSession(pSession, *this);
+    return new SchemaRouterSession(pSession, this);
 }
 
 void SchemaRouter::diagnostics(DCB* dcb)