Populate fuzz directory

$ mkdir -p fuzz/${PORTNAME}/png
$ cd fuzz/${PORTNAME}/png
$ cp -v /usr/local/share/afl/images/png/* input/
/usr/local/share/afl/images/png/hello_kitty_rle.png -> input/hello_kitty_rle.png
/usr/local/share/afl/images/png/hello_kitty_icc.png -> input/hello_kitty_icc.png
/usr/local/share/afl/images/png/hello_kitty_gamma.png -> input/hello_kitty_gamma.png
/usr/local/share/afl/images/png/hello_kitty_alpha.png -> input/hello_kitty_alpha.png
/usr/local/share/afl/images/png/hello_kitty.png -> input/hello_kitty.png