Start of new ANTLR4 based parser.

Very simple tests pass.

pglablib/sqlast/Node.h

@@ -0,0 +1,24 @@
+#pragma once
+
+namespace sqlast {
+
+    class Node {
+    public:
+        Node();
+        virtual ~Node() = default;
+
+    };
+
+}
+/*
+
+- Node
+  - INSERT
+  - UPDATE
+  - DELETE
+  - SELECT
+  - WITH
+  - CTE
+
+
+*/