压缩功能完成，单测通过
config changed
unit test
unit test
blob len < 0 bugfix
bug fix
Merge branch 'develop_branch2' of https://github.com/dianping/puma into develop_branch2
Merge pull request #5 from leoliang/develop_branch2

binlog, timestamp索引功能完成；数据文件压缩功能完成