修改了一处语病
First version of Comment part in chapter2/01_The_basics.md
update 02/01
修改错字和排版
First version of Semicolons part in Basics
Correct minor bug in Comment
Working on chapter  Classes and Structures

page 226 - 236 ：The Swift Programming Language.epub
Still working..
update content
update 02/01
add 2-19 Nested_Types

add 2-19 Nested_Types
add 3-1 AboutTheLanguageReference

add 3-1 AboutTheLanguageReference
update the content
Update README.md
Update README.md
add content of ARC
add arc content
bug fix
update arc content
Update README.md
Update README.md