Log Message:
Changes 3.0.16:
* Provide an option for prepending a standard prefix on dialling
* Implement start_iowatch() without a sigc::signal object (that is,
  using only a sigc::slot object for the callback)
* Corrections to syntax of efax-gtk.1 (man file) and
  efax-gtk.desktop.
* Add reference to -e option in efax man file
* Add more robust checking of whether an existing instance of
  efax-gtk is running when another instance is started
* Correct conditional compilation for use of GTK+ printing system to
  check for version 2.10
* Update comments on threading in prog_defs.h
* Update Catalan translation
* Update README file