sanger/sequencescape — pull request #509 by mattdenner (2012-05-11 19:02:14+00:00)
Title: 29448369 pulldown calling invalid fail state transitions on transfer requests

TransferRequest has a far less restrictive statemachine, and it's far
simpler too. This allows the pulldown application to transition much
more simply.

It does not fix the problem where the initial plate is cancelled from
the pending state, which needs the pulldown requests to have a special
statemachine too.