implement game configuration file

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

third-party/tomlc99/stdex/keys10.toml

@@ -0,0 +1,10 @@
+# VALID BUT DISCOURAGED
+
+apple.type = "fruit"
+orange.type = "fruit"
+
+apple.skin = "thin"
+orange.skin = "thick"
+
+apple.color = "red"
+orange.color = "orange"