bump fjall to 1.4.0

bump fjall to 1.2.0

Merge pull request #4 from marvin-j97/marvin-j97-patch-1

Update Cargo.toml

Update lib.rs

Update lib.rs

Update Cargo.toml

adjust key format

adjust max of space amp chart

rocksdb: on non-fsync, don't flush to OS buffers

fix fjall version

update readme

update fjall to v1

enable heed & rocksdb by default

update for fjall 1.0.0