Growable Storage & Secondary Keys

• Refactor nanots API for composite key support and format changes by @dicroce in #10

Growth

What's Changed

• Implement growable file allocation and management in nanots by @dicroce in #6

Full Changelog: v0.27.0...v0.28.0

Performance

Improved flushing behaviour on Windows.
Improved reader performance around local re-find()'s.

updates

amalgamated sources were not updated for the last release.
rust bindings work now.

db connection re-use

improves reader performance by re-using db connections.