update readme to include argparse-1 changes

Author: Jesse

README.md

@@ -5,11 +5,14 @@ A simple header only command line argument parser
 Here is a simple example
 
 ```cpp
-#include <iostream>
 #include "argparse.h"
 
+#include <iostream>
+#include <iterator>
+
 int main(int argc, char* argv[]) {
-  // run as: [program name] -a 1 -sdfl --flag -v 1 2.7 3 4 9 8.12 87 6
+  // run as: [program name] "0 -c" abc -a 1 -sdfl --flag -v 1 2.7 3 4 9 8.12 87
+  // [program name] -sdfv 1 -o "C:\Users\User Name\Directory - Name\file.dat" "C:\Users\User Name 2\Directory 2 - Name 2\file2.dat" C:/tmp/tmp.txt
   ArgumentParser parser("Argument parser example");
   parser.add_argument("-a", "an integer");
   parser.add_argument("-s", "an combined flag", true);
@@ -18,25 +21,39 @@ int main(int argc, char* argv[]) {
   parser.add_argument("--flag", "a flag");
   parser.add_argument("-v", "a vector", true);
   parser.add_argument("-l", "--long", "a long argument", false);
+  parser.add_argument("--files", "input files", false);
   try {
     parser.parse(argc, argv);
   } catch (const ArgumentParser::ArgumentNotFound& ex) {
     std::cout << ex.what() << std::endl;
     return 0;
   }
   if (parser.is_help()) return 0;
-  std::cout << parser.get<int>("a") << std::endl;
+  std::cout << "a: " << parser.get<int>("a") << std::endl;
   std::cout << "flag: " << std::boolalpha << parser.get<bool>("flag")
             << std::endl;
   std::cout << "d: " << std::boolalpha << parser.get<bool>("d") << std::endl;
   std::cout << "long flag: " << std::boolalpha << parser.get<bool>("l")
             << std::endl;
   auto v = parser.getv<double>("v");
+  std::cout << "v: ";
   std::copy(v.begin(), v.end(), std::ostream_iterator<double>(std::cout, " "));
-  if (v.size()) std::cout << std::endl;
+  double sum;
+  for (auto& d : v) sum += d;
+  std::cout << " sum: " << sum << std::endl;
+  auto f = parser.getv<std::string>("files");
+  std::cout << "files: ";
+  std::copy(f.begin(), f.end(),
+            std::ostream_iterator<std::string>(std::cout, " | "));
+  std::cout << std::endl;
+  f = parser.getv<std::string>("");
+  std::cout << "free args: ";
+  std::copy(f.begin(), f.end(),
+            std::ostream_iterator<std::string>(std::cout, " "));
+  std::cout << std::endl;
   return 0;
 }
 ```
 
 ## Compiling
-Just add `argparse.h` to your include path. Requires compiler support for `<regex>` (ex: g++>=4.9)
+Just add `argparse.h` to your include path. No longer requires compiler support for `<regex>`