Add version label to main menu

This adds a version label which displays the value of a project property.
The project property can be overriden using an override.cfg file.
This'll come in handy when we publish our releases, so we can display the actual version number in the main menu.

WIP #18

Scenes/MainMenu.tscn

@@ -1,5 +1,6 @@
-[gd_scene load_steps=8 format=2]
+[gd_scene load_steps=9 format=2]
 
+[ext_resource path="res://Scripts/Version.gd" type="Script" id=1]
 [ext_resource path="res://addons/gut/fonts/AnonymousPro-Bold.ttf" type="DynamicFontData" id=4]
 [ext_resource path="res://addons/gut/fonts/CourierPrime-Bold.ttf" type="DynamicFontData" id=5]
 [ext_resource path="res://Scripts/Menu.gd" type="Script" id=6]
@@ -27,6 +28,20 @@ transform = Transform2D( 1, 0, 0, 1, 0, 400 )
 autoScroll = true
 autoScrollSpeed = 200
 
+[node name="Version" type="Label" parent="."]
+anchor_top = 1.0
+anchor_right = 1.0
+anchor_bottom = 1.0
+margin_left = 10.0
+margin_top = -24.0
+margin_right = 57.0
+margin_bottom = -10.0
+text = "{version}"
+script = ExtResource( 1 )
+__meta__ = {
+"_edit_use_anchors_": false
+}
+
 [node name="MenuOptions" type="VBoxContainer" parent="."]
 anchor_top = 0.5
 anchor_bottom = 0.5
@@ -51,7 +66,7 @@ __meta__ = {
 [node name="Start" type="Button" parent="MenuOptions"]
 margin_top = 63.0
 margin_right = 248.0
-margin_bottom = 110.0
+margin_bottom = 119.0
 rect_min_size = Vector2( 122, 47 )
 size_flags_horizontal = 7
 size_flags_vertical = 7
@@ -61,9 +76,9 @@ flat = true
 align = 0
 
 [node name="Exit" type="Button" parent="MenuOptions"]
-margin_top = 114.0
+margin_top = 123.0
 margin_right = 248.0
-margin_bottom = 161.0
+margin_bottom = 179.0
 rect_min_size = Vector2( 122, 47 )
 size_flags_horizontal = 7
 size_flags_vertical = 7
@@ -76,6 +91,7 @@ __meta__ = {
 }
 
 [node name="SceneTransitionRect" parent="." instance=ExtResource( 7 )]
+visible = false
 anchor_top = 0.5
 anchor_right = 0.0
 anchor_bottom = 0.5

Scripts/Version.gd

@@ -0,0 +1,4 @@
+extends Label
+
+func _ready():
+	text = ProjectSettings.get_setting("global/version")

project.godot

@@ -23,6 +23,10 @@ window/stretch/aspect="expand"
 
 enabled=PoolStringArray(  )
 
+[global]
+
+version="local"
+
 [input]
 
 move_right={