Move pathfinding related code to ai.cpp.

Add a gsc.hpp header to allow creating methods and functions for GSC outside of the gsc component. Add experimental path generating code to ai.cpp.

src/component/gsc.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <stdinc.hpp>
+
+namespace gsc
+{
+	namespace
+	{
+
+	}
+
+	namespace function
+	{
+		void add(const std::string& name, const game::BuiltinFunction function);
+	}
+
+	namespace method
+	{
+		void add(const std::string& name, const game::BuiltinMethod method);
+	}
+}