v1.0.0-rc.1

Some breaking changes were introduced with `v1.0.0-rc.1`. Here is a migration guide:

## `appendTrack` has been renamed to `shiftTrack`.

before:
```typescript
const track = composition.appendTrack(VideoTrack);
```

after:
```typescript
const track = composition.shiftTrack(VideoTrack);
```

## `appendClip` has been renamed to `add`.

before:
```typescript
const clip = await composition.appendClip(new Clip());
// when using tracks
const clip = await track.appendClip(new Clip());
```

after:
```typescript
const clip = await composition.add(new Clip());
// when using tracks
const clip = await track.add(new Clip());
```

## `position` has been renamed to `layer` on the track object

before:
```typescript
const track = composition.appendTrack(VideoTrack).position('bottom');
```

after:
```typescript
const track = composition.shiftTrack(VideoTrack).layer('bottom');
```
# New Features

a new method for creating tracks has been introduced:

```typescript
const track = composition.createTrack('video');
// equivalent to
const track = composition.shiftTrack(VideoTrack);
```

This enabled us to add a new new method to the `MediaClip` for creating captions, which was previously not possible due to circular dependencies:

```typescript
const audio = new AudioClip(new File(), { transcript: new Transcript() });
await composition.add(audio);
await audio.generateCaptions();
```

> Note the `MediaClip` needs to be added to the composition for the generateCaptions method to be available.