chained references in <defs> are not properly handled

[vpadawan]

source file :

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg id="svg2" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" version="1.0" xmlns:xlink="http://www.w3.org/1999/xlink">
  <defs>
   <path id="a_line" stroke="#000000" d="M0,0 100,100"/>
   <g id="a_group"><use xlink:href="#a_line"/> <path stroke="#000000" d="M0,100 100,0"/></g>
  </defs>
  <use xlink:href="#a_group"/>
</svg>

output file :

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<svg id="svg2" xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100" version="1.0" xmlns:xlink="http://www.w3.org/1999/xlink">
 <defs>
  <g id="a_group"></g>
 </defs>
 <use xlink:href="#a_group"/>
</svg>

[codedread (codedread)]

Thank you for the unit test - this helps.

[codedread (codedread)]

Fixed in r156, will be release in scour 0.23