* scheme-options.texi (Evaluator options): Added evaluator

	* scheme-options.texi (Evaluator options): Added evaluator
	options, corrected docs for evaluator trap options.

	* scheme-evaluation.texi (Scheme Read): New docs for read-options,
	read-enable, read-disable and read-set! and cross references to
	option nodes.
	(Evaluator Options): New docs for eval-options, eval-enable,
	eval-disable and eval-set!, traps, trap-enable, trap-disable and
	trap-set! and cross references to option nodes.
	(Evaluator Behaviour): Renamed node from `Evaluator options' to
	avoid name clash.

	* scheme-io.texi (String Ports): Added docs for SRFI-6 procedures.
	(Void Ports): Corrected introductory comment.