* use simpler build.sbt format instead of Build.scala
  * use sbt-vaadin-plugin
Merge branch 'vaadin72' of https://github.com/strakz1/scaladin into strakz1-vaadin72

Conflicts:
	project/Build.scala
Merge branch 'strakz1-vaadin72' into 3.1
Defined scala version correctly, updated sbt version
* Made project to cross compile with scala 2.10 and 2.11
* Removed api using scala.xml stuff (because of scala 2.11)
Test both 2.10 and 2.11 with Travis CI
Minor changes to Dependencies.scala
Added PushConfiguration.Transport.LongPolling