bump version to 0.1.2

[haakon-e]

new minor version release for #20 (and probably other fixes too [see diff]).

Closes #22

[haakon-e]

Perhaps unrelated, it also seems like #3, #11, #18 can be closed.

I'd also recommend removing the Manifest.toml file as suggested in #21, which is typically only useful in the test/ directory (though it seems you don't have a separate Project.toml there)

[kouketsu]

Thank you for the comment.
The version has been bumped up with some minor changes.