Tested:

Tested:
  Move icon_descr to a reference-counted QString, freeing us from the horror
  of the 'is_dynamic? xfree()' mess and the issues in waypt_dupe.  The code
  is better in some ways, but suffers now while there are still a lot of
  const char*/QString edges, but there's only so much you can do in one commit
  and still keep the tree running.

  Builds Mac and Mingw-cross.  valgrind runs on Ubuntu.  (and caught a few
  errors as I introduced them.)