Add support for the GDScript language

References:
* https://github.com/okamstudio/godot/wiki/gdscript
* http://www.godotengine.org/

Some projects using it:
* https://github.com/okamstudio/godot
* https://github.com/Qwertie-/Godot-games

My motivation for adding it: To disambiguate these .gd
files from GAP .gd files.

samples/GDScript/pong.gd

@@ -0,0 +1,73 @@
+
+extends Node2D
+
+# member variables here, example:
+# var a=2
+# var b="textvar"
+const INITIAL_BALL_SPEED = 80
+var ball_speed = INITIAL_BALL_SPEED
+var screen_size = Vector2(640,400)
+#default ball direction
+var direction = Vector2(-1,0)
+var pad_size = Vector2(8,32)
+const PAD_SPEED = 150
+
+
+func _process(delta):
+
+
+	# get ball positio and pad rectangles
+	var ball_pos = get_node("ball").get_pos()
+	var left_rect = Rect2( get_node("left").get_pos() - pad_size*0.5, pad_size )
+	var right_rect = Rect2( get_node("right").get_pos() - pad_size*0.5, pad_size )
+	
+	#integrate new ball postion
+	ball_pos+=direction*ball_speed*delta
+	
+	#flip when touching roof or floor
+	if ( (ball_pos.y<0 and direction.y <0) or (ball_pos.y>screen_size.y and direction.y>0)):
+		direction.y = -direction.y
+		
+	#flip, change direction and increase speed when touching pads	
+	if ( (left_rect.has_point(ball_pos) and direction.x < 0) or (right_rect.has_point(ball_pos) and direction.x > 0)):
+		direction.x=-direction.x
+		ball_speed*=1.1
+		direction.y=randf()*2.0-1
+		direction = direction.normalized()
+
+	#check gameover
+	if (ball_pos.x<0 or ball_pos.x>screen_size.x):
+		ball_pos=screen_size*0.5
+		ball_speed=INITIAL_BALL_SPEED
+		direction=Vector2(-1,0)
+			
+						
+	get_node("ball").set_pos(ball_pos)
+
+	#move left pad	
+	var left_pos = get_node("left").get_pos()
+	
+	if (left_pos.y > 0 and Input.is_action_pressed("left_move_up")):
+		left_pos.y+=-PAD_SPEED*delta
+	if (left_pos.y < screen_size.y and Input.is_action_pressed("left_move_down")):
+		left_pos.y+=PAD_SPEED*delta
+		
+	get_node("left").set_pos(left_pos)
+		
+	#move right pad	
+	var right_pos = get_node("right").get_pos()
+	
+	if (right_pos.y > 0 and Input.is_action_pressed("right_move_up")):
+		right_pos.y+=-PAD_SPEED*delta
+	if (right_pos.y < screen_size.y and Input.is_action_pressed("right_move_down")):
+		right_pos.y+=PAD_SPEED*delta
+		
+	get_node("right").set_pos(right_pos)
+	
+	 
+
+func _ready():
+	screen_size = get_viewport_rect().size # get actual size
+	pad_size = get_node("left").get_texture().get_size()
+	set_process(true)
+