* Finish missing stdio functions

gets
fgetpos, fsetpos
mktemp, tmpfile, tmpname, L_tmpnam, TMP_MAX
perror
puts
remove
rename
FOPEN_MAX
FILENAME_MAX
getw, putw
fgetline? fpurge? snprintf? (sprintf w/limit) vsnprintf? (BSD)

* Optimize

String writes (printf, fwrite, sputn, fputs,puts,  ...)

* filebuf

Test and study for unusual uses: unbuffered files, putback,
seeking, read+write files, ...

* editbuf

Clear up memory use conventions.  Perhaps reference count marks.

* parsebuf

Clean up: Get rid of unused fields; nail down first-line conventions.

* iostream:

Define eofbit and badfile to use stream's eof and err flags?
Use width for input, precision.
Formatting of floats and doubles.
User-defined flags.
