Irregular inflector behavior

Hello there,

I have these rules (among others) in my app.

``` javascript
inflector.irregular('arma-branca', 'armas-brancas');
inflector.irregular('acessorio-arma-branca', 'acessorios-armas-brancas');
```

With this config I get this result:

It seems the second irregular rule is never met, this [line](https://github.com/stefanpenner/ember-inflector/blob/master/addon/lib/system/inflector.js#L270) looks like the culprit. It checks for the end of the rule, so, strings ending the same way can respond wrongly.

Another thing I notice is that this code makes the irregular declaration order specific. If I invert the order like so:

``` javascript
inflector.irregular('acessorio-arma-branca', 'acessorios-armas-brancas');
inflector.irregular('arma-branca', 'armas-brancas');
```

I get the right result:

Can we make the irregulars check for the whole expression first?