Updated some ports (AKuHAK):
libpng - updated to v1.5.17
libmad - fixed for building on Linux and made all files similar to the
original files.
libid3tag - removed obsolete files, fixed for building on Linux and made
all files similar to the original files.
madplay - fixed for building on Linux and made all files similar to the
original files.
romfs - update to v0.5.2.