added append docs from R4RS.
* strings.c: Docstring typo fix, + eliminate unneeded IMP tests.
Thanks Dirk Hermann!
* chars.h: Provide SCM_CHARP, SCM_CHAR, SCM_MAKE_CHAR and
deprecate SCM_ICHRP, SCM_ICHR, SCM_MAKICHR. Thanks Dirk Hermann!
* *.h, *.c: Use SCM_CHARP, SCM_CHAR, SCM_MAKE_CHAR throughout.
Drop use of SCM_P for function prototypes... assume an ANSI C
compiler. Thanks Dirk Hermann!
gdb_interface.h, gdbint.c, gdbint.h, gh_data.c, gh_init.c,
gh_io.c, gh_list.c, gh_predicates.c, gh_test_c.c, gh_test_repl.c,
init.c, net_db.c, options.c, options.h, ports.c, print.c, read.c,
script.h, snarf.h, srcprop.c, srcprop.h, stacks.c, stacks.h,
throw.c: Update copyright years; these files have been worked on
significantly in 1997, but only had copyright years for 1996.
Also, change name of copyright holder on some from Mikael
Djurfeldt to Free Software Foundation; he has signed papers
assigning the changes to the FSF.