SimplePingHelper with ARC and call by block

[shiweifu]

you can use SimplePingHelper like:

 [SimplePingHelper ping:@"www.apple.com"
callback:^(NSNumber *b){
if(b.boolValue)
{
NSLog(@"%@", @"success");
[self log:@"success"];
}
else
{
NSLog(@"%@", @"failure");
[self log:@"failure"];
}
}];

I also add ARC support