Support cross compilation to Scala.js 1.

Author: mikla

.travis.yml

@@ -10,6 +10,10 @@ jdk:
 sudo: required
 dist: trusty
 
+env:
+  - SCALAJS_VERSION=0.6.32
+  - SCALAJS_VERSION=1.0.0-RC2
+
 cache:
   directories:
     - $HOME/.ivy2

project/plugins.sbt

@@ -1,7 +1,11 @@
 resolvers += "Sonatype Public".at("https://oss.sonatype.org/content/groups/public/")
 
+val scalaJSVersion =
+  Option(System.getenv("SCALAJS_VERSION")).getOrElse("0.6.32")
+
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % scalaJSVersion)
+
 addSbtPlugin("org.portable-scala" % "sbt-scalajs-crossproject" % "0.6.1")
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "0.6.31")
 addSbtPlugin("com.typesafe.sbt" % "sbt-osgi" % "0.9.5")
 addSbtPlugin("com.github.gseitz" % "sbt-release" % "1.0.12")
 addSbtPlugin("org.xerial.sbt" % "sbt-sonatype" % "3.8.1")