implement game configuration file

this integrates https://github.com/cktan/tomlc99 into the repo as a dependency

third-party/tomlc99/stdex/keys08.toml

@@ -0,0 +1,5 @@
+# This makes the key "fruit" into a table.
+fruit.apple.smooth = true
+
+# So then you can add to the table "fruit" like so:
+fruit.orange = 2