Feature alias name

We want WebTrends to track when a feature is on/off. To avoid exposing the real and descriptive feature names via the html meta tags, I have added an `alias_name` method to feature definitions. Those features that need WebTrends tracking should also declare an `:alias_name` like so:

```
feature :item_quality_complexity,
  :alias_name => :a_not_so_obvious_name
```