列表：（1）- (NSString *)stringByAddingPercentEscapesUsingEncoding:(NSStringEncoding)encoding
（2）UIAlertView 、ActionSheet 在iOS9 中由 UIAlertController取代
（3）NSURLConnection sendSynchronousRequest.../sendAsynchronousRequest... deprecated,现在只能使用NSURLSession
（4）stretchableImageWithLeftCapWidth:topCapHeight: deprecated in iOS2.0,
use resizableImageWithCapInsets：
（1）- (NSString *)stringByAddingPercentEscapesUsingEncoding:(NSStringEncoding)encoding
原用法：
NSString *urlString = @"jianshu.com";
urlString = [urlString stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSURL *url = [NSURL URLWithString:urlString];
新用法：
For Objective-C：
NSString *str = ...; // some URL
NSCharacterSet *set = [NSCharacterSet URLHostAllowedCharacterSet];
NSString *result = [str stringByAddingPercentEncodingWithAllowedCharacters:set];
取代
来源：http://stackoverflow.com/questions/32242712/replacement-for-stringbyaddingpercentescapesusingencoding-in-ios9
（2）UIAlertView 、ActionSheet 在iOS9 中由 UIAlertController取代
另：UIAlertController 可增加UITextField
来源：http://stackoverflow.com/questions/32690086/uialertview-first-deprecated-ios-9
（3）NSURLConnection sendSynchronousRequest/sendAsynchronousRequest deprecated,现在只能使用NSURLSession
http://stackoverflow.com/questions/32441229/nsurlconnection-deprecated-in-ios9
（4）http://jayrparro.com/blog/2012/05/17/stretchable-images-in-ios-5
