mediatrace: isn't parsing into the MKV Cues element

[dericed]

The Matroska demuxer is only summarizing the size of the Cues element but not reporting on its contents.

This sample file contains a CRC32 element as a child of Cues but it is unreported. For the Cues Element, this is all that is reported:

<block offset="35763194" name="Cues" size="145">
  <block offset="35763194" name="Header" size="6">
    <data offset="35763194" name="Name">206814059</data>
    <data offset="35763198" name="Size">139</data>
  </block>
  <data offset="35763200" name="Cues data, skipping">(139 bytes)</data>
</block>

This prevents a possible Cues/CRC32 from being validated. Additionally the contents of Cues contain many requirements that should be tested either via xsl or via the demuxer directly.