Be smarter about callable imports/exports

[DanielRosenwasser]

Unfortunately the esModuleInterop flag doesn't have a smaller check which just yells at users when they call/construct an import *.

Maybe this package could do that and provide a good error message?

It isn't legal in ES2015+ to call/construct a namespace import (something declared with the syntax `import * as foo from 'foo'`). Could you please convert your import to use the following syntax?

```ts
import foo = require('foo')
```

Alternatively, you can use a default import like the following with `esModuleInterop` turned on:

```ts
import foo from 'foo';
```