saturn: prevent buttons from expanding vertically when few apps

On my phone there are only five apps installed, and FlowBox
stretches the buttons in weird ways unless told not to

Also delete unused local

saturn/main.fnl

@@ -131,15 +131,15 @@
  (lgi.GObject.Closure (fn [a] (print "get")))
  (lgi.GObject.Closure (fn [a] (print "set"))))
 
-(local grid-columns 4)
-
 (let [grid (Gtk.FlowBox {
-                      :column_spacing 2
-                      :row_spacing 5
-                      })
+                         :orientation Gtk.Orientation.HORIZONTAL
+                         :valign Gtk.Align.START
+                         :column_spacing 2
+                         :row_spacing 5
+                         })
       scrolled-window (Gtk.ScrolledWindow {})]
   (each [_ app (pairs (all-apps))]
-      (grid:insert (button-for app) -1))
+    (grid:insert (button-for app) -1))
   (scrolled-window:add grid)
   (window:add scrolled-window))