Merge pull request #63 from arainko/use-runtime-checked

use `.runtimeChecked` instead of unchecked

Merge pull request #46 from arainko/renaming-docs

add renaming docs

Merge pull request #18 from arainko/issue-6-either-traversals

[Issue #6] add support for Either travelsals

'Result:'-less README

pass over some unhappy path cases, make the erorrs EVEN NICER, don't …

…publish 'root'