1, add content for chapter 12\n 2, delete unnecessary *.pyc files in exts
delete unnecessary *.pyc files in exts
add .gitignore
Merge pull request #32 from jinglong/master

update chapter 12
update log in README
Merge pull request #33 from jinglong/master

update readme
fix the wrong date in log
Merge pull request #34 from jinglong/master

fix the wrong date in log
Update chapter_11.rst
Update README.rst
Update index.rst
Update chapter_02.rst
Fixed some typos.
Merge pull request #43 from fanjizhao/master

Fixed issue-40 and issue-41