NSAutoreleasePool for CCFileUtils functions

Hi,
i have the suggestion to use NSAutoreleasePool for CCFileUtils functions, only for iOS devices obviously.
I know that cc2dx does not support multithreading now, but it should be usefull(like in my case).

for example:
without NSARpool

std::string CCFileUtils::getWriteablePath()
    {
        // save to document folder
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        std::string strRet = [documentsDirectory UTF8String];
        strRet.append("/");
        return strRet;
    }

with NSARpool

std::string CCFileUtils::getWriteablePath()
    {
        NSAutoreleasePool* pool = [[NSAutoreleasePool alloc] init];

        // save to document folder
        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
        NSString *documentsDirectory = [paths objectAtIndex:0];
        std::string strRet = [documentsDirectory UTF8String];

        [pool release]; pool = nil;

        strRet.append("/");
        return strRet;
    }

what do you think about this?

P.S.:if you find some grammar errors, replace them with smiles in your mind =)

Thank you.
#1116 is created.