Addressed implementation defined behaviour in rng function

Properly handle the results of the rng output as unsigned ints, rather than relying on implementation defined conversion from unsigned to signed integers

duel.cpp

@@ -131,13 +131,13 @@ void duel::set_response(const void* resp, size_t len) {
 }
 // uniform integer distribution
 int32_t duel::get_next_integer(int32_t l, int32_t h) {
-	const int32_t range = h - l + 1;
-	const int32_t lim = random.max() % range;
-	int32_t n;
+	const uint32_t range = h - l + 1;
+	const uint32_t lim = random.max() % range;
+	uint32_t n;
 	do {
-		n = random();
+		n = static_cast<uint32_t>(random());
 	} while(n <= lim);
-	return static_cast<int32_t>((n % range) + l);
+	return static_cast<int32_t>(n % range) + l;
 }
 duel::duel_message* duel::new_message(uint8_t message) {
 	return &(messages.emplace_back(message));