Finish up wc(1)

Use size_t for all counts, fix the manpage and refactor the code.
Here's yet another place where GNU coreutils fail:

sbase:
$ echo "GNU/Turd sucks" | wc -cm
    15

coreutils:
$ echo "GNU/Turd sucks" | wc -cm
     15      15

Take a bloody guess which behaviour is correct[0].

[0]: http://pubs.opengroup.org/onlinepubs/009604499/utilities/wc.html

README

@@ -82,7 +82,7 @@ The following tools are implemented ('*' == finished, '#' == UTF-8 support,
 =  sha1sum         non-posix                       none
 =  sha256sum       non-posix                       none
 =  sha512sum       non-posix                       none
-   wc              yes                             none
+#* wc              yes                             none
 =  xargs           no                              -I, -L, -p, -s, -t, -x
 =* yes             non-posix                       none