Missing count

`diff.diffLines('var a = 0;', 'var a = 0;\nvar b = 1;\nvar c = 3')` returns

```
[{
 added: undefined,
 count: 1,
 removed: true,
 value: "var a = 0;",
},
{
 added: true,
 count: 3,
 removed: undefined,
 value: "var a = 0;↵var b = 1;↵var c = 3",
}]
```

`diff.diffLines('', 'var a = 0;\nvar b = 1;')` returns

```
[{
 added: true,
 value: "var a = 0;↵var b = 1;",
}]
```

what happened to count?
