Fixing broken plural support

Looks like plurals were slightly broken since the upgrade to CLDR v24.  The code for English plurals produced the following results:

```ruby
n = 1
(n.to_i.to_s.length == 1 && ((v = n.to_s.split(".")).count > 1 ? v.last.length : 0) == 0) ? :one : :other
# returns :one
```
So far so good.  But what about when `n = 2`?

```ruby
n = 2
(n.to_i.to_s.length == 1 && ((v = n.to_s.split(".")).count > 1 ? v.last.length : 0) == 0) ? :one : :other
# returns :one as well
```

The problem stems from the fact that the `i` operand means "integer digits of `n`".  It's currently being treated as the number of integer digits in `n`, which is incorrect.  See [UTS 35](http://www.unicode.org/reports/tr35/tr35-numbers.html#Language_Plural_Rules) for details.