Merge pull request scala#2542 from rjolly/scripting12

Read-eval-print : the script engine does not need print so make it lazy

Author: paulp

src/repl/scala/tools/nsc/interpreter/IMain.scala

@@ -899,7 +899,7 @@ class IMain(@BeanProperty val factory: ScriptEngineFactory, initialSettings: Set
       val preamble = """
       |object %s {
       |  %s
-      |  val %s: String = %s {
+      |  lazy val %s: String = %s {
       |    %s
       |    (""
       """.stripMargin.format(