Refactor sponge(1) code and manpage

and mark it as finished in README.

README

@@ -61,7 +61,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =* sleep           yes                             none
    sort            no                              -m, -o, -d, -f, -i
 =* split           yes                             none
-=  sponge          non-posix                       none
+=* sponge          non-posix                       none
    strings         no                              -a, -n, -t
 =* sync            non-posix                       none
 =  tail            no                              -c, -f

sponge.1

@@ -1,4 +1,4 @@
-.Dd January 30, 2015
+.Dd February 8, 2015
 .Dt SPONGE 1
 .Os sbase
 .Sh NAME
@@ -14,7 +14,6 @@ reads stdin completely, then writes the saved contents to
 This makes it possible to easily create pipes which read from and write to
 the same file.
 .Pp
-If the given
+If
 .Ar file
-is a symbolic link, it writes to the links destination
-instead.
+is a symbolic link, it writes to its destination instead.

sponge.c

@@ -1,6 +1,5 @@
 /* See LICENSE file for copyright and license details. */
 #include <stdio.h>
-#include <stdlib.h>
 
 #include "text.h"
 #include "util.h"