Developer friendly NPM package

[micheldebree]

Retropixels as a library is not developer friendly to use. It is not clear how to import the different classes. It is also not documented. Todo:

Make sure classes can be imported the usual way, f.e.

import {Converter} from 'retropixels';

Documentation is out of scope.

[micheldebree]

See https://github.com/basarat/ts-npm-module-consume and https://stackoverflow.com/questions/30928253/writing-npm-modules-in-typescript