Only count eligible promotions towards Promotion#credits

Fixes #4120
Append omega to content classes

Fixes #4179
Order#available_payment_methods should also return payment methods marked as 'Both'

Fixes #4199
Add changelog for #4199
Bump acts_as_list to 0.3.0
Convert credit card expiry values to integers

Fixes #4188
Change UserLoggedInRule to use presence of a user as its check

The logic goes that if the user is signed in, then the order will be associated to that user (through the magic of associate_user). Therefore, if an order has a user then the user has been signed in at some point in the past. If the user is not signed in, only 'email' would be set for the user
make sure that we deduct the correct amount when the calculable is order same as done with the line_items.

Fixes #4105
Add missing translation save_my_address
Ensure duplicate payment methods are not returned by Order#available_payment_methods
Actually assert association settings in product_spec