Multi-line selectors not working

Rule blocks with multiple selectors on more than one line do not produce the correct results.
For example, with v1 file of
```
h1,
h2 {
    background: blue;
}
```
And a a v2 file of 
```
h1,
h2 {
    background: white;
}
```
The result is
```
h2 {
    background: blue
}
```
Notice that only the last selector (h2) is in the output.
