Merged languagesAllowed & supportedLanguages

Merged languagesAllowed & supportedLanguages into supportedLocales while retaining deprecated support for older config options.

Added a few new functions that deprecate older functions that I couldn't alter without destroying backwards compatibility.  Also renamed a few values to locale and localeCode to help avoid confusion due to the new function.

This is fairly thoroughly tested, but please take the time to run tests before merging.

This should resolve the first step of https://github.com/mcamara/laravel-localization/issues/30