Make a kind of ICS text menu in XBoard as a dialog

Make a kind of ICS text menu in XBoard as a dialog

The dialog with buttons can be opened from the View menu. It is
configured by the option -icsMenu; a default setting for this is
included in the master settings file.
  The commands specified by the -icsMenu can now contain $name and $input
keywords, which will be replaced by the current primary selection, or
text the user types, respectively. Commands that contain $name will not
be sent when the current selection is empty. Commands that do not
contain $input will be sent to the ICS immediately; otherwise they will
be placed in the ICS Input Box, with the cursor at the point of the
$input, and input focus given to the Input Box, so the user can start
typing. When a command is prefixed by "$add " it will be appended to the
existing ICS Input Box contents, rather than replace it.
  The items now have to be separated by ";\n", and button text from
command by ';' (with optional linefeed). This allows configuring of
multi-line commands, as a single linefeed no longer has special
sigificance.