Optimization code
[#348] display event history on event show page
[#348] add related spec
[#348] add I18n support
followers fix #340
test code for followers #340
[#348] Refactor: move view related method to help module, also moving related spec
Merge pull request #351 from loveky/master

#348 显示往期活动记录
[#357] add link to event edit page in event show page
merge.
show event menu bar.
add tabs_on_rails gem.
used new layout in checkin view
Optimization code #350
fixed rspec error.
Merge pull request #360 from saberma/add_event_menu_bar

显示活动管理菜单
email participant fix #350
email participant job 2 fix #350
test code for email participant fix #350
merge with newest master code #350
Optimization code2 #350