Fails to build without the snap feature enabled

`cargo auditable install crabz --no-default-features --features=deflate_rust` results in the following error: ``` error[E0599]: no variant or associated item named `Snap` found for enum `Format` in the current scope --> /home/shnatsel/.cargo/registry/src/github.com-1ecc6299db9ec823/crabz-0.8.1/src/main.rs:264:21 | 150 | enum Format { | ----------- variant or associated item `Snap` not found for this enum ... 264 | Format::Snap => ("sz", string_set!["sz", "snappy"]), | ^^^^ variant or associated item not found in `Format` For more information about this error, try `rustc --explain E0599`. ```