title: SBT exclude scala-library.jar from a war file packaged using xsbt-web-plugin
body: <p>I have a project that only needs to take a proguard-constructed jar file, which is built in a separate SBT project and contains all classes needed to run as a servlet, and create a war file out of it.</p>
  
  <p>The dependency is properly packaged into the war, and the transitive jars are excluded correctly using notTransitive(), but scala-library.jar continues to be placed into the war file as well.  This is not desired, since the proguard-built jar contains those scala classes that are necessary for the servlet filter to run.  The present project just needs to take that dependent jar, add a web.xml, and package it into a war file.</p>
  
  <p>What is the simplest way (preferably using a build.sbt file) to get the war packaging mechanism from the xsbt-web-plugin to exclude the scala-library.jar?</p>