Merge pull request #119 from niandy/master

Map key can be any comparable type now

Merge pull request #111 from andrewpmartinez/add.v2.for.generics

adds v2 to module name, fixes readme

Merge pull request #107 from ImVexed/master

Support for 1.18 generics

Merge pull request #98 from orcaman/calc_key_length_once

Calc key length once