put config block in a function, add config for gui and update example conf

example/controldeck.conf

@@ -2,7 +2,7 @@
 #
 # [N.volume.NAME]
 # name = sink_name
-# : N.    optional group/row specification
+# : N.    optional number to specify group/row
 # : NAME  name of the button
 # : name  sink name, see name with either:
 #           pactl list sinks short
@@ -16,5 +16,19 @@
 # : NAME     name of the button
 # : command  command(s) to run
 
+[gui]
+width = 800
+height = 600
+# x and y specifying the window coordinate (empty = centered)
+x =
+y =
+resizable = True
+fullscreen = False
+min_width = 200
+min_height = 100
+frameless = False
+minimized = False
+always_on_top = False
+
 [4.button.Test]
 command = notify-send -a foo baz