the string tokenisation must be performed by the caller (which is
generally easy because it's almost always a static command).
* change do_conversion() to return a char *argv[] instead of char *cmd.
tokenisation of the command is done internally.
* change retrieve() to take char *argv[] instead of char *cmd.
(to take advantage of the above changes). fixes [bin/8173]
* use fparseln() instead of fgetln()
* store conversions in listed order (rather than reverse order)
* use stringlists instead of handrolling code to manage an argv.
397e2cfc53