v0.3.0

What's Changed

• add csv support by @romeokienzler in #46
• implement #45 (single string cos connection), support pluggable grid wrapper backends, implement s3kv backend by @romeokienzler in #47
• [WIP] fix constant name issue by @romeokienzler in #48

Full Changelog: v0.2.9...v0.3.0