Whitelist package contents

[MatthiasKunnen]

Instead of blacklisting unwanted files for npm packing (.npmignore), whitelist wanted ones. Blacklisting, by nature, can easily result in unwanted files getting packed. Case in point, the package currently contains the following files:

node_modules/typedjson
├── coverage ❌
│   └── lcov.info ❌
├── js
│   ├── parser.d.ts
│   ├── typedjson
│   │   ├── deserializer.d.ts
│   │   ├── helpers.d.ts
│   │   ├── json-array-member.d.ts
│   │   ├── json-map-member.d.ts
│   │   ├── json-member.d.ts
│   │   ├── json-object.d.ts
│   │   ├── json-set-member.d.ts
│   │   ├── metadata.d.ts
│   │   ├── options-base.d.ts
│   │   ├── serializer.d.ts
│   │   ├── to-json.d.ts
│   │   └── types.d.ts
│   ├── typedjson.d.ts
│   ├── typedjson.js
│   ├── typedjson.js.map
│   ├── typedjson.min.js
│   └── typedjson.min.js.map
├── license.md
├── nyc.config.js  ❌
├── .nyc_output ❌
│   ├── 24892588-7b80-4b20-b951-42179426f7df.json ❌
│   ├── a16100f3-cb79-4c53-abcc-a04a89fa0d53.json ❌
│   └── processinfo ❌
│       ├── 24892588-7b80-4b20-b951-42179426f7df.json ❌
│       ├── a16100f3-cb79-4c53-abcc-a04a89fa0d53.json ❌
│       └── index.json ❌
├── package.json
└── readme.md

 ❌ marks files that I believe to be added erroneously

About the files key in package.json: files such as the readme get packed by default, see https://docs.npmjs.com/files/package.json#files. Testing which files are going to be packed can be done using npm pack.

[Neos3452]

Thanks a lot!