Make error messages more verbose

[tremby]

If I'm running riscosarc over lots of files at once and one of them errors, the error message as it stands doesn't tell me which file failed to decompress, just "Invalid archive file" for example. It'd be nice if messages mentioned the filename, I think!

(I concede that I could check the exit code in a script, but that's unwieldy if I just want to run a find -exec.)

[mjwoodcock]

It's a valid request. I shall look at that tonight. Should be a simple fix.

[mjwoodcock]

This is fixed in the latest version of the code. Let me know if you are happy.

[tremby]

Looks good to me!