Manual payment processing

[gduda]

It should be possible to manually register payment that came via different channel than supported in the system. It would be great if it can be also automated. For example by uploading CSV file with registrationIDs and paid amounts and system should mark corresponding registrations as Paid.
Whenever system can't match registrationID and amount of payment, it should be reported to the admin.

[syjer]

edit: moving my comment to a more appropriate task :D

[cbellone]

done.