Add MACRO which calls exit(0) on any runtime_error in parse_args

include/argparse.hpp

@@ -671,4 +671,11 @@ class ArgumentParser {
     std::map<std::string, std::shared_ptr<Argument>> mArgumentMap;
 };
 
+#define PARSE_ARGS(parser, argc, argv) \
+try { \
+  parser.parse_args(argc, argv); \
+} catch (const std::runtime_error& err) { \
+  exit(0); \
+}
+
 }