query domains in transaction report for HeartBeatAlert
refactor alert summary module
Merge pull request #582 from jialinsun/master

add doc & refactor
modify the tese case
Merge pull request #583 from youyong205/master

modify the tese case
refactor cache report
Merge branch 'master' of https://github.com/dianping/cat
Merge pull request #584 from leonindy/master

fix serval bugs found in code review
Merge branch 'master' of https://github.com/dianping/cat
clean code