Adding Scala examples for Chapter 3 (#28)

* Add files via upload

* Update 01_countdown.scala

* Update 02_greet.scala

* Update 02_greet.scala

03_recursion/scala/02_greet.scala

@@ -0,0 +1,16 @@
+def greet2(name: String): Unit = {
+  println("how are you, " + name + "?")
+}
+
+def bye(): Unit = {
+  println("ok bye!")
+}
+
+def greet(name: String): Unit = {
+  println("hello, " + name + "!")
+  greet2(name)
+  println("getting ready to say bye...")
+  bye()
+}
+
+greet("adit")