Disable 'liga' for vertical text

The reason we turned it on is because Kazuraki uses it.  But that's
not reason enough.  Until the OpenType spec gets its act together re
adding design-direction to lookups, this is better user experience.

src/hb-ot-shape.cc

@@ -43,7 +43,6 @@
 
 static hb_tag_t common_features[] = {
   HB_TAG('c','c','m','p'),
-  HB_TAG('l','i','g','a'),
   HB_TAG('l','o','c','l'),
   HB_TAG('m','a','r','k'),
   HB_TAG('m','k','m','k'),
@@ -56,6 +55,7 @@ static hb_tag_t horizontal_features[] = {
   HB_TAG('c','l','i','g'),
   HB_TAG('c','u','r','s'),
   HB_TAG('k','e','r','n'),
+  HB_TAG('l','i','g','a'),
   HB_TAG('r','c','l','t'),
 };