Allow the saving of hash results to a file

[Chewie9999]

It would be great if once hashing has been completed, you could right-click on one of the checksums and get an option to save it to a file, with a prompt for filename (default would be current filename.xxx, where xxx is the usual extension for the particular hash algorythm, eg .md5 or .sha1).
I get many files or download that don't come with checksum files, so I have to create my own, and it would be great to be able to do this from gtkhash directly.

[tristanheaven]

It's possible to save the result of all enabled algorithms to a file using the menu (File->Save).

I hadn't thought of adding an option to save a single checksum that way. Should be quite simple to implement.