removed pointless cast
Generating IntelliJ IDEA  parameter completion DSL.

However, due to a bug in IDEA, this doesn't actually result in an useful completion. See the ticket I field on IDEA: http://youtrack.jetbrains.com/issue/IDEA-108375 and http://youtrack.jetbrains.com/issue/IDEA-108355
Modified to produce a jar file instead of WEB-INF/classes

Because of the prefetching change in remoting  (see JENKINS-15120), it
is desirable now to produce class files in a jar file, not in a classes
directory, so that slaves can prefetch them and cache them efficiently.