Created the loadGameMap() function, still incomplete

Although the overall logic of this function is finished, I still need to
write the callbacks for RegionPager's onNew and onDelete.

I've also tested this using a hand written save/index file. I've written
up a map file format by hand, and I'll be implementing it over the next
few commits.

common/utility.cpp

@@ -51,3 +51,9 @@ std::string to_string_custom(int i) {
 	snprintf(buffer, 20, "%d", i);
 	return std::string(buffer);
 }
+
+int to_integer_custom(std::string s) {
+	int ret = 0;
+	sscanf(s.c_str(), "%d", &ret);
+	return ret;
+}