v0.2.0 - Avoid allocations

• Main change: use str::from_utf8 instead of String::from_utf8 wherever possible. This will avoid unnecessary allocations.
• This also allowed direct usage of &[u8] instead of Vec<u8> in multiple places, for additional efficiency.

Breaking Change

• Removed (undocumented) to_utf8_lossy function since we only plan to support valid utf8 data for ease of use. We might introduce another serializer / deserializer that can handle arbitrary bytes later on, but this should be clear that it uses another implementation altogether.

Full Changelog: v0.1.1...v0.2.0