API changes on xboxleaders.com

Hi,

seems like xboxleaders.com changed the way their API works. [http://api.xboxleaders.com/](http://api.xboxleaders.com/) returns NXDOMAIN when trying to resolve the hostname.

According to their [API Docs](http://www.xboxleaders.com/docs/api/) the correct way to query their Profile API is the following:

    http://www.xboxleaders.com/api/profile.json?gamertag=fooforge
    #or
    http://www.xboxleaders.com/api/profile/fooforge.json

I updated the fetch method in order to be able to retrieve profile information once again.

I "forked" the gem for testing purposes. Head over to [rubygems.org](https://rubygems.org/gems/ffo_gamertag) to give it a try before merging this.

Also, their API now exposes achievements, friends and games. It's probably not necessary anymore to query two different services to get the relevant information. I'd give it a try to simplify (and extend the gem) if you don't mind.


Regards,
Mike