When a request for storage times out (not enough slots filled), the client will initiate a withdraw request to retrieve its funds out of the contract, setting the state of the request to RequestState.Cancelled. The client will also emit a RequestCancelled event for others to listen to (ie hosts will need to listen for this event to withdraw its collateral).
Add unit test that checks for emission of RequestCancelled after request is purchased request expires.
Update dagger-contracts dependency to commit that holds the changes supporting withdrawing of funds.
- rename `ContractId` to `SlotId`
- add `RequestId`, `PurchaseId`, `Nonce` types as aliases of `array[32, byte]`
- rename `Proving.contracts` to `Proving.slots`
- change signatures of `isSlotCancelled` and `isCancelled` to use `SlotId` and `RequestId` types, respectively.
- change all references to `RequestId`, `SlotId`, and `PurchaseId`
Eric Mastro
Mark Spanbroek
Michael Bradley