title: Why is SBT NOT excluding these libraries despite using excludes?
body: <p>Despite doing the following, sbt is still grabbing lift-json. Why?</p>
  
  <pre><code>"net.liftweb" %% "lift-mapper" % "2.6-M4" % "compile" excludeAll(ExclusionRule("net.liftweb", "lift-json"))
  </code></pre>
  
  <p>More info. This is what dependency tree shows:</p>
  
  <pre><code>+-net.liftweb:lift-mapper_2.10:2.6-M4
  [info]   | +-net.liftweb:lift-db_2.10:2.6-M4
  [info]   | | +-net.liftweb:lift-util_2.10:2.6-M4
  [info]   | | | | 
  …
  [info]   | | | |   
  [info]   | | | +-net.liftweb:lift-json_2.10:2.6-M4
  </code></pre>
  
  <p>So dependency is lift-mapper -> lift-db -> lift-util -> lift-json, perhaps exclusion is not deep?</p>