发送短信，发邮件，打电话代码实现
基础代码：

打电话：
    + (void) sendEmail:(NSString *)phoneNumber    {        NSURL *phoneNumberURL = [NSURL URLWithString:[NSString stringWithFormat:@"mailto:%@", phoneNumber]];        NSLog(@"send sms, URL=%@", phoneNumberURL);        [[UIApplication sharedApplication] openURL:phoneNumberURL];       }    + (void) sendEmail:(NSString *)to cc:(NSString*)cc subject:(NSString*)subject body:(NSString*)body    {        NSString* str = [NSString stringWithFormat:@"mailto:%@?cc=%@&subject=%@&body=%@",                         to, cc, subject, body];        str = [str stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];               [[UIApplication sharedApplication] openURL:[NSURL URLWithString:str]];           }