continuations-plugin cross suffixed by 2.11.0, rather than than 2.11

To remedy the error:

    Unable to resolve artifact: Missing:
    ----------
    1) org.scala-lang.plugins:scala-continuations-plugin_2.11:jar:1.0.1

In:

  https://scala-webapps.epfl.ch/jenkins/view/scala-release-2.11.x/job/scala-release-2.11.x/56/console
Merge pull request #99 from retronym/topic/continuations-cross

continuations-plugin cross suffixed by 2.11.0, rather than than 2.11