file() accepts glob pattern ("*en.php"); multiple files for one language in "languages" folder.

I updated "file()" so that it can also accept glob pattern ("*en.php") 
and include (require) all matched files. Totally backwards compatible.

The reason for this is to allow multiple files for one language in
"languages" folder. Now I can translate my plugin like this:

site/languages/plugin-name.en.php
site/languages/plugin-name.ru.php

and keep other translations in the same folder:
site/languages/en.php
site/languages/ru.php

and they all will load together. Handy!