Add puzzler 54 as a test

Author: odersky

tests/run/puzzler54.scala

@@ -0,0 +1,13 @@
+// Scala Puzzler 54
+object Test {
+  case class Card(number: Int, suit: String = "clubs") {
+    val value = (number % 13) + 1 // ace = 1, king = 13
+    def isInDeck(implicit deck: List[Card]) = deck contains this
+  }
+
+  def main(args: Array[String]) = {
+    implicit val deck = List(Card(1, "clubs"))
+    implicit def intToCard(n: Int): Card = Card(n)
+    assert(1.isInDeck)
+  }
+}