Added registration.

Currently doesn't return any valid result, hence host believes device
failed to register, however, insecure storage of keys does occur.

U2F_Init_CMD.cpp

@@ -0,0 +1,21 @@
+#include "U2F_Init_CMD.hpp"
+#include <stdexcept>
+#include "U2FMessage.hpp"
+#include "u2f.hpp"
+
+using namespace std;
+
+U2F_Init_CMD U2F_Init_CMD::get()
+{
+	const auto message = U2FMessage::read();
+
+	if (message.cmd != U2FHID_INIT)
+		throw runtime_error{ "Failed to get U2F Init message" };
+	else if (message.data.size() != INIT_NONCE_SIZE)
+		throw runtime_error{ "Init nonce is incorrect size" };
+
+	U2F_Init_CMD cmd;
+	cmd.nonce = *reinterpret_cast<const uint64_t*>(message.data.data());
+
+	return cmd;
+}