fix bugs
Merge pull request #30 from daolm/master

fix bugs daolm
Merge pull request #31 from HoangThiTuanDung/master

fix date, delete relation table dunghtt
Statistic_question
Statistics
Merge pull request #32 from xhunterx89/master

Statistics thanhpx
Statistics-2
Merge pull request #33 from xhunterx89/master

Statistics-2
Merge pull request #34 from HoangThiTuanDung/master

Multi select dunghtt
Statistics-3
Merge branch 'master' of https://github.com/tranducliem/smf
Merge pull request #35 from xhunterx89/master

Statistics-3
delete feedbackmanager
Merge branch 'master' of https://github.com/tranducliem/smf
fix delete relation table