Create wpt-rmsym, removes unwanted <sym> entries from GPX files

Squashed commit of the following:

  commit 5b5f9c4a66fbb89c365968ff6da7d171b43482c4
  Author: Øyvind A. Holm <sunny@sunbase.org>
  Date:   Thu Apr 17 02:31:02 2014 +0200

      wpt-rmsym: Make it work

      Reads from stdin and sends output to stdout.

      94834efe-c5c7-11e3-9c7d-000df06acc56

  commit 4c49403a3fc553eaa6afb9dd1edbcf692368bc01
  Author: Øyvind A. Holm <sunny@sunbase.org>
  Date:   Thu Apr 17 02:14:41 2014 +0200

      std -l bash wpt-rmsym

      4c0d5a4a-c5c5-11e3-a733-000df06acc56

dd7179aa-c5c8-11e3-9681-000df06acc56