use the app level documents directory instead of /var/mobile

This is a big change in that it changes the RetroArch system path where
it saves settings, game saves, etc. Using /var/mobile meant that
RetroArch only ran on jailbroken devices. This was the only thing
requiring a jailbreak.

Now not only will it work on vanilla devices, but all settings etc are
neating found in the app's documents directory.
enable iTunes File Sharing

Turning on iTunes File Sharing means being able to easily drop roms
into the app by dragging them in via iTunes.
dot the system directory to hide it from iTunes Sharing

This esssentially hides the retroarch system directory when viewing the
documents directory through iTunes Sharing.

You can't browse folders this way anyways, so having it visible is
essentially useless anyways.

You can of course still get to this directoy via tools like iTools
(non-jailbroken) or ssh'ing into the device (jailbroken).
i did!
open directly to the Documents directory
ignore dotted files/dirs including '.' and '..'
Merge pull request #159 from maddox/non-jailbreak

Enable for Non-Jailbroken Phones