Merge branch 'dev' of https://github.com/OpenWaterAnalytics/EPANET into copy-dev-swig

src/epanet.c

@@ -4737,7 +4737,7 @@ int DLLEXPORT EN_addnode(EN_ProjectHandle ph, char *id, EN_NodeType nodeType) {
       }
     }
   } else {
-    nIdx = net->Nnodes++;
+    nIdx = net->Nnodes+1;
     node = &net->Node[nIdx];
     coord = &net->Coord[nIdx];
     net->Ntanks++;