Finish chap2 check. some typo checked. some order fixed (to suit Chinese Grammer).
Merge pull request #9 from DeathKing/master

Finish chap2 check. some typo checked. some order fixed (to suit Chinese...
Merge pull request #10 from xiehuc/master

finish chapter function
some typo fixed. some order changed.
fixed till line 4045. fixed some typo. two _what_ retranslate.
Merge pull request #11 from DeathKing/master

Yet another pull request from DeathKing
begin chapter 15 objects
complete 15.1
finish 15.2 Attributes
finish 15.3-Rectangles
finish 15.4-Instances as return values
finish 15.5-Objects are mutable
finish 15.6-copy
finish 15.7-Debugging
finish 15.8-Glossary
类型对象 -> 类对象
finish chapter 15. Classes and objects
fix a mistake
fix a mistake
fix some mistakes in chap.15