modify pattern code style
a trivial change
correct attributes grammar
correct declarations  grammar
modify [a swift tour] code style
modify
modify right back
fix 2.1 the basics
fix 2.2 basic operators
fix 2.3 Strings_and_Characters
fix 2.4 Collection_Types
统一标准
fix 2.5 Control_Flow
fix 2.5 Control_Flow(2)
fix 2..6 Functions
fix 2.7 closures
fix 2.7 closures(2)
fix 他
fix 2.8 Enumerations
fix 2.9 classes and structures