patch 8.0.0159: crash on startup when updating tabline

Problem:    Using a NULL pointer when using feedkeys() to trigger drawing a
            tabline.
Solution:   Skip drawing a tabline if TabPageIdxs is NULL. (Dominique Pelle)
            Also fix recursing into getcmdline() from the cmd window.
diff --git a/src/version.c b/src/version.c
index 38be7db..f1a36da 100644
--- a/src/version.c
+++ b/src/version.c
@@ -765,6 +765,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    159,
+/**/
     158,
 /**/
     157,