spaceblaster: added beam class

I should have added this earlier...

games/spaceblaster/beam.py

@@ -0,0 +1,15 @@
+# Bryan Schumaker (12 / 31 / 2010)
+
+from engine import image
+from engine import object
+load = image.load
+GO   = object.GameObject
+
+class Beam(GO):
+	def __init__(self, GAME, type, pos):
+		GO.__init__(self, load(GAME, "beam-%s.png" % type), pos, (0, 1))
+		self.allow_offscreen = True
+		self.min_y -= self.h
+
+	def move(self):
+		self.move_y(-1)