Auto Loading Libraries

so i have a Multi Module application , and i want to include any libraries to my project . my structure is like so :

| apps
| config
| libraries
    | PHPMailer
        | phpmailer.php
        | smtp.php

    | Mustache
        | Autoloader.php ( just to simplify not gonna pul the whole dir )
| public

i managed to make phpmailer work by namespaceing it and calling it in my controller , but how can i load all of the files from mustache without needing to namespace all files and including to my controller?

I think $loader->registerDirs(array(/path/to/Mustache/) should do the trick