Upgrade junit_xml_listener to 0.5.1 which fixes the following issues

1) fix the class name to be fully qualified classpath
2)  make sure the the reporting time is in second not in miliseond, which causing JUnit HTML to report incorrect number
3)  make sure the duration of the tests are accumulative.

Author: DB Tsai

project/plugins.sbt

@@ -21,6 +21,6 @@ addSbtPlugin("org.scalastyle" %% "scalastyle-sbt-plugin" % "0.4.0")
 
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.1.6")
 
-addSbtPlugin("com.alpinenow" % "junit_xml_listener" % "0.5.0")
+addSbtPlugin("com.alpinenow" % "junit_xml_listener" % "0.5.1")
 
 addSbtPlugin("com.eed3si9n" % "sbt-unidoc" % "0.3.0")