TypeScript support

According to GitHut, TypeScript is now the #5th most popular language on github:
https://madnight.github.io/githut/#/pull_requests/2020/3

Can you either add types directly to the package or update documentation on how to do it manually?

```
npm install cli-table
npm install --save @types/cli-table
```

tsconfig.json
```
{
"compilerOptions": {
"esModuleInterop": true
}
}
```

index.ts
```
import Table from 'cli-table';
```

You'll save every developer 10 minutes :)