Switch to cmake + vcpkg, builds on linux, windows needs verification.

Code has been modified to be portable.

pglab/querytool/QueryExplainModel.cpp

@@ -40,7 +40,7 @@ if (role == Qt::DisplayRole) {
 				result = item->estimateError();
 				break;
 			case c_ColumnRowCount:
-				result = item->actualRows;
+				result = QVariant::fromValue(item->actualRows);
 				break;
 			case c_ColumnLoops:
 				result = item->actualLoops;