Update to sol2 v2.20.6

third_party/sol2/examples/wip/lua_inheritance.cpp

@@ -0,0 +1,19 @@
+#define SOL_CHECK_ARGUMENTS 1
+#include <sol.hpp>
+
+#include "../assert.hpp"
+#include <iostream>
+
+int main(int, char*[]) {
+	std::cout << "=== lua inheritance ===" << std::endl;
+
+	sol::state lua;
+	lua.open_libraries(sol::lib::base);
+
+	/* This example is currently under construction.
+	For inheritance and classes within Lua, 
+	consider using kikito's middleclass
+	-- https://github.com/kikito/middleclass */
+
+	return 0;
+}