implement game configuration file

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

third-party/tomlc99/stdex/string1.toml

@@ -0,0 +1,9 @@
+str1 = """
+Roses are red
+Violets are blue"""
+
+# On a Unix system, the above multi-line string will most likely be the same as:
+str2 = "Roses are red\nViolets are blue"
+
+# On a Windows system, it will most likely be equivalent to:
+str3 = "Roses are red\r\nViolets are blue"