Added "Functions" Chapter. Rename some files.

Added "Functions" Chapter,
Rename some files.
Each chapter has one corresponding file.
merged
Added "Functions" Chapter. Rename some files.

Added "Functions" Chapter,
Rename some files.
Each chapter has one corresponding file.
merged
Merge branch 'translate-swift' of https://github.com/honghaoz/the-swift-programming-language-in-chinese into translate-swift
Rename strings_and_characters.md to Strings_and_Characters.md
completed "Defining and Calling Functions"
Merge pull request #14 from honghaoz/translate-swift

Added "Functions" Chapter. Rename some files.
make the structure standard
Update README.md
first para
Update README.md
Update README.md
add some origin
Add: Closures
修改了一处语病
First version of Comment part in chapter2/01_The_basics.md
Merge pull request #19 from pyanfield/develop

修改了一处语病
Merge pull request #20 from JaySurplus/gh-pages

First version of Comment part in chapter2/01_The_basics.md
update 02/01