goesimage loses error codes from the processes that it runs

[yurivict]

For example, at some point convert began to fail and the goesimage still succeeds, and it doesn't print any message saying that the child process failed.

[pigmonkey]

Does the latest master work for you? I'm only wrapping curl, feh, and convert. Doing it for more common utils like mkdir and file seems like overkill, but I suppose we could wrap those as well.

I'm not returning the exit code of the failed process, as they may conflict with the exit codes returned by goesimage.

[yurivict]

Thanks for fixing this.