renamed mobiledevice.c to mobiledevice.m
use NSString and ARC to simplify mobiledevice.c(m)
avoid printing (nil) and the ? operator
correct typo:reverted by error the status
Merge pull request #5 from leopatras/master

simplify mobiledevice.c -> rename to mobiledevice.m and use NSSttring instead of CFString and ARC