Add propane and initial skeleton grammar

src/fart.propane

@@ -0,0 +1,28 @@
+tree;
+
+token height;
+token lcurly;
+token options;
+token rcurly;
+token scene;
+token width;
+
+token uint /\d+/;
+
+Start -> Options? Scene;
+
+Height -> height uint;
+
+Options -> options lcurly OptionsItems rcurly;
+
+OptionsItems -> ;
+OptionsItems -> OptionsItem OptionsItems;
+
+OptionsItem -> Height;
+OptionsItem -> Width;
+
+Scene -> scene lcurly SceneItems rcurly;
+
+SceneItems -> ;
+
+Width -> width uint;