Fixes for Blip's Access & Invitations feature branch

Hey @jh-bate, let me know what you think:

Instead of going from raw received invites objects that have:

```javascript
{
  // ...
  "creatorId": "11"
}
```

To:

```javascript
{
  // ...
  "creatorId": "11",
  "creator": {"fullName": "Mary Smith"}
}
```

I'd like to completely replace the `creatorId` with a **full user object**:

```javascript
{
  // ...
  "creator": {
    "userid": "11",
    "profile": {"fullName": "Mary Smith"}
  }
}
```

I'm trying to follow this consistency of "user objects" (at the top-level, a "userid" field, and a "profile" blob; if the user is you, you also have your "username" and "emails"), throughout the app and APIs...

/cc @ianjorgensen