Updated to default to 50k digits with no arguments, Makefile updates

main.cpp

@@ -5,8 +5,8 @@
 int main(int argc, char **argv) {
     int numDigits = 0;
     if(argc < 2) {
-        std::cout << "Usage: spigot <numDigits>" << std::endl;
-        return -1;
+        numDigits = 50000;
+        std::cout << "Defaulting to 50000 digits..." << std::endl;
     } else {
         numDigits = std::atoi((const char *)argv[1]);
     }