Cant import `zeroLength`

```
WARNING in ./node_modules/@nativescript-community/ui-svg/index.common.js 41:20-30
export 'zeroLength' (imported as 'zeroLength') was not found in '@nativescript/core'
```

Fix:

```
import { CoreTypes } from '../../core-types';

// ...

this.left = CoreTypes.zeroLength;
this.top = CoreTypes.zeroLength;
```

