Add a Scala.js example.

Author: kz0817

scalajs/ex1/build.sbt

@@ -0,0 +1,7 @@
+enablePlugins(ScalaJSPlugin)
+
+name := "Scala.js Tutorial"
+scalaVersion := "2.12.6" // or any other Scala version >= 2.10.2
+
+// This is an application with a main method
+scalaJSUseMainModuleInitializer := true

scalajs/ex1/project/build.properties

@@ -0,0 +1 @@
+sbt.version=0.13.17

scalajs/ex1/project/plugins.sbt

@@ -0,0 +1 @@
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.26")

scalajs/ex1/src/main/scala/tutorial/webapp/TutorialApp.scala

@@ -0,0 +1,7 @@
+package tutorial.webapp
+
+object TutorialApp {
+  def main(args: Array[String]): Unit = {
+    println("Hello world!")
+  }
+}