extra files in Atutor package
I recently downloaded Atutor 2.2. After I extracted the package, I see in the extracted folders, for each file of Atutor there is another file with te same name but started by "._". For instance there is login.php and there is also ._login.php. And this is about all files even images. I don't know are these necessary for Atutor or there wassomething wrong in the extracting. And can I delete them?