patch 8.0.0660: silent install on MS-Windows shows dialog

Problem:    Silent install on MS-Windows does show a dialog.
Solution:   Add /SD to the default choice. (allburov, closes #1772)
diff --git a/nsis/gvim.nsi b/nsis/gvim.nsi
index 74a5433..9ace4ea 100644
--- a/nsis/gvim.nsi
+++ b/nsis/gvim.nsi
@@ -87,7 +87,7 @@
 Function .onInit
   MessageBox MB_YESNO|MB_ICONQUESTION \
 	"This will install Vim ${VER_MAJOR}.${VER_MINOR} on your computer.$\n Continue?" \
-	IDYES NoAbort
+	/SD IDYES NoAbort
 	    Abort ; causes installer to quit.
 	NoAbort:
 
diff --git a/src/version.c b/src/version.c
index cb4ac7f..877a1c5 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    660,
+/**/
     659,
 /**/
     658,