Option to override language file

[kmbriedis]

Adds an option to create custom language file in directory mentioned in https://laravel.com/docs/5.2/localization#overriding-vendor-language-files, to override existing or creating new language file in Laravel 5.1 and 5.2.

Solves issue #188

[danhunsaker]

I would strongly recommend documenting direct usage of the $resource parameter, so non-Laravel projects know how they can take advantage of this enhancement as well.

[kmbriedis]

@danhunsaker does the last commit solve what you meant or did you mean more explict documentation?

[danhunsaker]

Not quite. It's good for Laravel users to know, but still doesn't address non-Laravel users. These users will be better served by knowing they can pass the $resourcePath to Date:setLocale() manually, which will let them put those files wherever makes sense for their own projects, instead of being forced into Laravel's paradigm.