HTML_dump: Skip imgs with an empty src (<score> causing nullpointerexception)

[desb42]

I have managed to produce a full build of enwiki (including html)
I have also added lillypond executable to provide <score> interpretation

This seems to have lead to an issue in the html version of en.wikipedia.org/wiki/Symphony_No._9_(Beethoven)

<java.lang.NullPointerException> null
[trace]:
  gplx.Io_mgr.ExistsFil(Unknown Source)
  gplx.xowa.htmls.core.Xow_hdump_mgr__load.Fill_page(Unknown Source)
  gplx.xowa.htmls.core.Xow_hdump_mgr__load.Load_by_xowe(Unknown Source)

it seems that the html generated has text of the form

<p>
  <a id="xowa_score_0_a" href="" xowa_title="">
    <img id="xowa_score_0_img" src=""  />
  </a>
</p>

by adding

if (itm.Orig_ttl() == null) continue;

at line 129 of 400_xowa\src\gplx\xowa\htmls\core\Xow_hdump_mgr__load.java it loads the page without error

[gnosygnu]

Thanks for the simple fix! Corrected with the commit above!