Some eyes on these changes?

I very shamelessly added myself to the gemspec :-)

Added:

```ruby
point.distance_to(other_point)
# these exist on CGRect, but didn't on CGSize
size.wider(10)
size.thinner(10)
size.taller(10)
size.shorter(10)
```

I know I have push access and all that, but there's nothing wrong with a pull request, either, right!? :smile: