Allow to run via ts-node (#73)
* Allow to run via ts-node
* Enhance readmes
* Streamline test infos in readme
* Streamline building infos in readme
* re-add all js extensions
* make sure that ts errors when not provided
* add comments
* Update package.json
it must not be that way else requiring breaks, but so we loose the checks for ".js" file endings because TS only considers it wrong with that ... need to check deeper - but could also be added in extra PR
* make cjs working and also ts checks
* minimize package.json change
* address review feedback
