Update 03Types.md
Merge pull request #1 from CocoaChina-editors/master

更新翻译
Merge pull request #2 from CocoaChina-editors/master

合并更新
Update 03Types.md
Merge pull request #3 from CocoaChina-editors/master

合并更新
Update 17Optional Chaining.md
Update 17Optional Chaining.md
翻译初稿

第一次翻译，虚心接受建议
Merge pull request #53 from Lin-H/master

翻译初稿
Update 17Optional Chaining.md
调整段落

调整段落
Update 17Optional Chaining.md

This raw version is alpha and needs to be retouched by myself later. Any suggestions and blame plz @狙击手 in the group.
Merge pull request #54 from Jasonbroker/master

02章17节更新
Merge pull request #1 from CocoaChina-editors/master

简单raw版本
校正部分翻译
Merge branch 'master' of https://github.com/CocoaChina-editors/Welcome-to-Swift
Update 17Optional Chaining.md
Merge pull request #55 from Jasonbroker/master

some adjustments
Using Swift with Cocoa and Objective-C chapter 3
修复图片链接