Using a global variable to register meta types instead of the main() function.

Prevents needing to have extra includes in the main.

src/pglab/QueryTab.h

@@ -33,6 +33,7 @@ public:
 	QueryParamListController(QTableView *tv, OpenDatabase *opendb, QWidget *parent);
 
 	Pgsql::Params params() const;
+    bool empty() const;
 public slots:
 	void on_addParam();
 	void on_removeParam();