First usable generator source.

Still issues with usage rules and error reporting, but functional.

generator/demo/main.cpp

@@ -0,0 +1,19 @@
+{{=@@ @@=}}
+#include "@@argspec@@ArgGrammarDriver.hpp"
+#include <sstream>
+
+using Result = @@argspec@@ArgGrammar::Driver::Result;
+
+int main(int argc, char* argv[]) {
+	@@argspec@@ArgGrammar::Driver driver{ argc, argv };
+	auto res = driver.parse();
+
+	if (res != Result::success) {
+		if (res == Result::completedAction)
+			return 0;
+
+		return -1;
+	}
+
+	return 0;
+}