added alpha component to Color

src/net/bdew/lib/gui/Color.scala

@@ -11,10 +11,11 @@ package net.bdew.lib.gui
 
 import org.lwjgl.opengl.GL11
 
-case class Color(r: Float, g: Float, b: Float) {
+case class Color(r: Float, g: Float, b: Float, a: Float = 1) {
   def this(c: (Float, Float, Float)) = this(c._1, c._2, c._3)
+  def this(c: (Float, Float, Float, Float)) = this(c._1, c._2, c._3, c._4)
   def activate() {
-    GL11.glColor3f(r, g, b)
+    GL11.glColor4f(r, g, b, a)
   }
 }