Ensure QR codes have a border large enough

(The QR code spec requires a border at least 4*box_size thick but we can't
 just set border=16 because that results in a QR code more than 255px tall
 and I'm not yet ready to use fullimage() as a backend for it)

This fix was originally commited by Stephan Sokolow on 2014-05-22

examples/qr_code.py

@@ -0,0 +1,16 @@
+from escpos.printer import Usb
+
+
+if __name__ == '__main__':
+
+    # Adapt to your needs
+    p = Usb(0x0416, 0x5011, profile="POS-5890")
+
+    # Some software barcodes
+    p.set(align='left')
+
+    p.text("hello\n")
+
+    p.qr("https://github.com/python-escpos/python-escpos")
+
+    p.text("world\n")

src/escpos/escpos.py

@@ -203,7 +203,10 @@ class Escpos(object):
             qr_img = qr_code.make_image()
             im = qr_img._img.convert("RGB")
             # Convert the RGB image in printable image
+            self.text('\n')
             self.image(im)
+            self.text('\n')
+            self.text('\n')
             return
         # Native 2D code printing
         cn = b'1'  # Code type for QR code