Add ability to print your Tox ID's QR code to a file

src/qr_code.h

@@ -0,0 +1,35 @@
+/*  qr_code.h
+ *
+ *
+ *  Copyright (C) 2015 Toxic All Rights Reserved.
+ *
+ *  This file is part of Toxic.
+ *
+ *  Toxic is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  Toxic is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with Toxic.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef QR_CODE
+#define QR_CODE
+
+#define QRCODE_FILENAME_EXT ".QRcode"
+
+/* Converts a tox ID string into a QRcode and prints it to the given file stream.
+ *
+ * Returns 0 on success.
+ * Returns -1 on failure.
+ */
+int ID_to_QRcode(const char *tox_id, FILE *fp);
+
+#endif /* QR_CODE */