CORRECTION: interactive-coffeescript.html Exercise 18 Solution

file: interactive-coffeescript.html
Exercise 18
Solution:

``` coffeescript
oldestCat = (data) ->
  oldest = null
  for name of data
    cat = data[name]
--- unless 'death' of cat
+++ unless 'death' in cat
      if oldest is null or oldest.birth > cat.birth
        oldest = cat
  oldest?.name
show oldestCat catData
```
