Allow editing of campaign for recurring contributions AND financial type for simple contributions

The contribution_recur table stores these 2 fields - but the edit recurring contribution page does not currently allow them to be edited. The ticket is to add editability and to update the repeattransaction api to. Editability will only be permitted if there is a single line item.

1) accept contribution_recur_id as a parameter
2) lookup the recurring contribution record for the campaign_id & financial_type_id (single line item only) rather than the original contribution record.
3) campaign_id is currently accepted as a parameter - where provided this will continue to take precedence.

The altered code is in the IPN code so is also accessed by paypal, authorize.net