cross-build with 2.11 and 2.12

Author: lrytz

.travis.yml

@@ -1,6 +1,6 @@
 language: scala
 
-script: sbt clean update test publishLocal
+script: sbt clean update +test +publishLocal
 jdk:
   - openjdk6
   - openjdk7

build.sbt

@@ -6,7 +6,9 @@ name                       := "scala-xml"
 
 version                    := "1.0.5-SNAPSHOT"
 
-scalaVersion               := "2.11.4"
+scalaVersion               := crossScalaVersions.value.head
+
+crossScalaVersions         := Seq("2.11.6", "2.12.0-M1")
 
 // important!! must come here (why?)
 scalaModuleOsgiSettings