gridmicrotex 0.1.1

• The typeface fallback is now a message rather than a warning, is raised only when render_mode = "typeface" was actually asked for, and at most once per device. A figure holding many math labels no longer repeats it.
• Bug fix: the layout engine's macro tables were never freed. They leaked at process exit, and unloadNamespace() left both them and the shared object in place. All are now released.