Use consistent generic parameter name

Refactor API so that keys are generic (#6)

perf: use vek32 for SIMD-based speedup on amd64

Unfortunately, they don't have an ARM implementation yet.

Fix Export/Import comments

Some vestiges from the Gob implementation

Add persistence

Solved #3

README: update first link to something more approachable

Thx @stirby

Add godoc link and LICENSE