Fix regression test and sort order for identical selectors (#14)

@christiaan the fix applied in #14 by @csnover doesn't actually work - the intention is correct, but your regression test seems to cater to the given solution, not the needed one. If you give this as input:
```css
ul { color: blue; }
ul { color: red; }
```
We would expect the resultant inline rule to be ```color: red```, correct?
Simply returning 1 instead of 0 in this case _actually_ means that the earlier selector is considered 'greater than' later selectors, and is thus bumped _down_ the sort order so that it is always sorted _after_ later rules instead of _before_.

The confusion may have come about from a version prior to the fix in #7, which altered the merge order? Not sure.

I've updated the regression test as well.