implement game configuration file

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

third-party/tomlc99/stdex/string3.toml

@@ -0,0 +1,15 @@
+# The following strings are byte-for-byte equivalent:
+str1 = "The quick brown fox jumps over the lazy dog."
+
+str2 = """
+The quick brown \
+
+
+  fox jumps over \
+    the lazy dog."""
+
+str3 = """\
+       The quick brown \
+       fox jumps over \
+       the lazy dog.\
+       """