Fixes bugs in examples (#1997)
Fixes bugs in examples (#1997)

`URL.appendPathComponent` is mutating; the example is set up to use the generating version `URL.appendingPathComponent`.
iosheadhunter/Alamofire,iosheadhunter/Alamofire,Alamofire/Alamofire,richardPFisk/Alamofire,richardPFisk/Alamofire,easyui/Alamofire,yimajo/Alamofire,antigp/Alamofire,Alamofire/Alamofire,Lomotif/Alamofire,Lomotif/Alamofire,jschmid/Alamofire,yimajo/Alamofire,antigp/Alamofire,jschmid/Alamofire,easyui/Alamofire