就想簡單的使用Keychain忘蟹，不需要Keychain Access Group 斗塘，也不需要其他復(fù)雜的應(yīng)用欣舵，
就想簡單的保存?zhèn)€用戶名和密碼之類的，
就想像用NSUserDefaults 那樣來存儲數(shù)據(jù)揭鳞。
Methods as follows:
+(BOOL)setObject:(id)object forKey:(NSString *)key;
+(id)objectForKey:(NSString *)key;
+(BOOL)deleteItmeWith:(NSString*)key;
Set Item:
[SimpleKeychain setObject:@"value" forKey:@"key"];
Get Item:
[SimpleKeychain objectForKey:@"key"];
Delete Item:
[SimpleKeychain deleteItmeWith:@"key"];
