Do not show *nix hidden files (. prefix)

[dankcushions]

It seems ES will display hidden files in the gamelist, causing confusion for at least one user: https://retropie.org.uk/forum/topic/4863/noob-looking-for-help-change-emulators-graphics-and-get-things-working/14. i've seen it on my system also.

it looks like it only cares that the extension is correct. eg, ._Aladdin.smc would be displayed in the SNES gamelist.

i think the only reason you would have hidden files in your rom folders would be a failed transfer (i believe i encountered it when a transfer via OSX/samba failed), which wouldn't be a valid file, so safe to hide I think.

[dankcushions]

fixed via #183