Deriving `Error` with `Eq`

[Nekidev]

It's a little thing and it's good for ergonomics when checking whether an error occurred or if the row did not exist when using ::get() to be able to do

match result {
    Ok(_) => unimplemented!(),
    Err(e) => {
        if e == Error::NoSuchObject {
            // ...
        } else {
            // ...
        }

        // VS.

        match e {
            Error::NoSuchObject => {
                // ...
            },
            _ => {
                // ...
            }
        }
    }
}

It's prettier than having to nest another match to check for one of all the possible errors (less lines of code and less nesting for the same purpose). This is implemented by deriving the Error enum with:

#[derive(PartialEq, Eq)]
pub enum Error {
    ...

[Electron100]

@Nekidev like this? #373

[Electron100]

Sorry, I was far too hasty. This doesn't build because some of the inner types don't implement even PartialEq