Taking input from stdin

[rikonor]

Hi!

I saw https://github.com/monostream/tifig/issues/18 which deals with outputting to stdout, are there any plans to update the tool to allow reading the image from stdin instead of a file?

When shelling out to tifig from other languages it's nice to be able to provide the input via stdin, since sometime the image is already in memory. Currently, the calling program has to create a temporary file and put the image in there for tifig to read from.