title: mvn dependency:tree doesn't really show all dependencies
body: <p>I ran into an issue compile a jar with many dependencies, in particular overlapping versions of <code>snakeyaml</code> (we need 1.11, some dependency was pulling in 1.9).  We ran <code>mvn dependency:tree</code> but we did not see the offending secondary version in any of the output.  On further inspection, is was <code>jruby-complete</code> that was then pulling in <code>snakeyaml</code>.  Why didn't <code>mvn dependency:tree</code> show us this level of drill down:</p>
  
  <pre><code>[INFO] |     |  +- org.apache.hbase:hbase-it:jar:0.98.6-cdh5.2.5:compile
  [INFO] |     |  |  +- (org.apache.hbase:hbase-common:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  +- (org.apache.hbase:hbase-protocol:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  +- (org.apache.hbase:hbase-client:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  +- org.apache.hbase:hbase-shell:jar:0.98.6-cdh5.2.5:compile
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-common:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-protocol:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-client:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-prefix-tree:jar:0.98.6-cdh5.2.5:runtime - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-server:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-hadoop-compat:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hbase:hbase-hadoop2-compat:jar:0.98.6-cdh5.2.5:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (com.yammer.metrics:metrics-core:jar:2.2.0:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (commons-logging:commons-logging:jar:1.1.1:compile - omitted for conflict with 1.2)
  [INFO] |     |  |  |  +- org.jruby:jruby-complete:jar:1.6.8:compile
                                &gt;&gt;&gt;&gt;&gt;&gt;&gt; WHY ARE THERE NO DEPENDENCIES HERE? &gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;
  [INFO] |     |  |  |  +- (org.cloudera.htrace:htrace-core:jar:2.04:compile - omitted for duplicate)
  [INFO] |     |  |  |  +- (org.apache.hadoop:hadoop-common:jar:2.5.0-cdh5.2.5:compile - omitted for duplicate)
  </code></pre>
  
  <p>Why wasn't <a href="http://search.maven.org/#artifactdetails%7Corg.jruby%7Cjruby-complete%7C1.6.8%7Cjar" rel="noreferrer">the dependencies of jruby-complete</a> listed in the tree?  Does <code>mvn dependency:tree</code> only gfo to a certain depth?  What are the rules here?  If <code>mvn dependency:tree</code> had simply shown us its <code>snakeyaml</code> dependency we could have saved a couple hours of complex debugging.  </p>