Major speed improvement, split the project into several files

preferences.py

@@ -0,0 +1,24 @@
+import gi
+from gi.repository import Gtk
+
+import util
+
+class ModelPreferenceView(Gtk.Popover):
+    def __init__(self, on_gpu_change=None, *args, **kwargs):
+        super().__init__(*args, **kwargs)    
+        self.on_gpu_change = on_gpu_change
+        
+        box = Gtk.Box(orientation=Gtk.Orientation.VERTICAL, spacing=6)
+        util.set_margin_all(box, 8)
+
+        label = Gtk.Label(label="GPU Layers")
+        box.append(label)
+        
+        gpu_spin = Gtk.SpinButton(adjustment=Gtk.Adjustment(
+            value=15, lower=0, upper=50, step_increment=1,
+        ), digits=0, hexpand=True)
+
+        gpu_spin.connect("value-changed", lambda spin: self.on_gpu_change(spin.get_value_as_int()))
+        box.append(gpu_spin)        
+        
+        self.set_child(box)