OC版版本检测对比大小最简代码，抄自iVersion

@implementation NSString(iVersion)

• (NSComparisonResult)compareVersion:(NSString *)version
  {
  return [self compare:version options:NSNumericSearch];
  }

• (NSComparisonResult)compareVersionDescending:(NSString *)version
  {
  return (NSComparisonResult)(0 - [self compareVersion:version]);
  }

@end