Merge pull request #2 from liuzhi123004/master

liuzhi认领第二章第一节
认领2.2
Merge pull request #3 from mengyanyl/master

认领2.2
readme
Merge branch 'master' of https://github.com/enilu/hadoopdoc.git
enilu认领01.2
翻译1.1，1.2章节
Merge branch 'master' of https://github.com/enilu/hadoopdoc.git
enilu认领任务1.3
Merge pull request #1 from enilu/master

合并主版本代码