patch 8.1.0713: images for NSIS take up too much space

Problem:    Images for NSIS take up too much space.
Solution:   Put the images in a zip file.
diff --git a/src/version.c b/src/version.c
index aaf12c2..1f9d809 100644
--- a/src/version.c
+++ b/src/version.c
@@ -800,6 +800,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    713,
+/**/
     712,
 /**/
     711,