one:WxH semantif filename
Merge branch 'master' of https://github.com/carlodef/iio
save int-valued images
save int pngs (woth loss of precision)
read images into int arrays
minor fix to make piio.read/write compatible with unicode strings

example:

    piio.read(u'/tmp/lena.png')

now works, as well as:

    piio.read('/tmp/lena.png')

You don't need to type:

    piio.read(str(u'/tmp/lena.png'))