Implementation of operations

Operation.operation() is a structured sequence of deferreds.
Operation.stateManagement() maintains state of input & output items.
Operation.transfers() handles transferring quantities.
Fixed a bug in the tube resource initialisation.
Fixed an issue in root so that it picks up actions
Added transfer models to handle transfer decoding.
Added tube rack movement handling.
Merge pull request #55 from mattdenner/implementing_operations

Implementation of operations