Network Merchants - Added remote tests and cleaned up code

- Added remote tests for track data / fixed one
- Refactored some code network_merchants so useless data is not sent
- All remote tests pass

@j-mutter @jnormore @louiskearns 
hm.. I think it might be needed here as I get an exception when I take it out... The track_data method doesn't exist on creditcard_or_vauld_id.. I don't get why it doesn't get thrown in the usa_epay code...