update chapter23 method 1
Merge pull request #1 from julycoding/master

2014-01-14
Merge pull request #138 from liuyang1/master

update chapter23 method 1
Update 02.0.md
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Merge pull request #139 from cpcs/master

第二章
Merge pull request #2 from julycoding/master

同步作者的更新
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Merge pull request #140 from liuyongkang/master

Update 02.0.md
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Merge remote-tracking branch 'upstream/master'