Replace failure with thiserror

[akhilles]

failure seems to be deprecated and there are some compelling reasons to use thiserror instead:

• Better interoperability with other error wrapping solutions since thiserror doesn't introduce any custom traits
• It simply derives std::error::Error which means compatibility isn't broken if it's replaced down the road
• Better suited for libraries since it doesn't affect the public API and works well with anyhow

I would have opened an issue to discuss this, but I was already using the forked version so decided to just submit a PR.

[jean-airoldie]

I think that's its fine if the Debug implementation of Error does not output the content. So you could add a separate manual implementation such as:

impl fmt::Debug for Error {
    fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
        fmt.debug_struct("Error")
           .field("kind", &self.kind)
           .finish()
    }
}

This would allow the T: Debug bound to be removed everywhere.

[jean-airoldie]

Looks good. Can I merge?

[akhilles]

Looks good. Can I merge?

Yup!

[jean-airoldie]

Good stuff! I'll do a release.