title: scald.rb results in error (could not find or load main class)
body: <p>I am trying to run the tutorial files from <a href="https://github.com/twitter/scalding/tree/develop/tutorial" rel="nofollow noreferrer">https://github.com/twitter/scalding/tree/develop/tutorial</a>.
  I cloned the 0.17.x branch and current develop branch and haven't had much success with either.</p>
  <p>I have also already ran &quot;sbt update&quot; and &quot;sbt assembly&quot; to create the fat jar which is used by this scald.rb script.</p>
  <p>Upon running the command below from the root scalding directory</p>
  <pre><code>scripts/scald.rb --local tutorial/Tutorial0.scala
  </code></pre>
  <p>I receive either of these errors:</p>
  <pre><code>Error: Could not find or load main class Files
  [SUGGESTION]: Try scald.rb --clean, you may have corrupt jars lying around
  </code></pre>
  <p>or</p>
  <pre><code>Error: Could not find or load main class scala.tools.nsc.Main
  [SUGGESTION]: Try scald.rb --clean, you may have corrupt jars lying around
  </code></pre>
  <p>Whatever I try to do I cannot get the scald.rb script to work. I have tried the clean option and many other stackoverflow answers such as setting scala_home in my environment variables and path to scala/bin. Many versions of sbt/scala and nothing works.</p>
  <h3>Current Software:</h3>
  <p>-Ruby 2.4.2-2-x86</p>
  <p>-sbt 0.13.15</p>
  <p>-Scala 2.11.8</p>
  <p>-scalding 0.17.x branch</p>