disabled order button if event has started.
order button label change to [finished] if event has started.
change free order status to paid.
create a default ticket after event created.
remove join js.
fixed rspec error.
add money angular filter.
add event started? method.
Merge pull request #489 from saberma/saberma-enhancement/468-remove-sidebar-join-button

去掉右边栏的报名按钮