Funds should be returned to payers if target not met

[patriacaelum]

Since owners can deploy a proposal without meeting a minimum horizon, the process of the proposal inverter is effectively split into two phases:

1. The "Fundraising" phase, where the proposal remains stagnant until enough funds have accumulated to meet the minimum requirements.
2. The "Research" phase, where the proposal begins to allocate funds to the committed brokers.

Should the "Fundraising" phase not reach its target in a timely manner, the owner of the proposal may choose to cancel the proposal. In this case, the funds should be returned to the payers.

• In the ProposalInverter.cancel() method, if ProposalInverter.started is False, then the funds in the ProposalInverter.payer_contributions should be reallocated to their respective payers and all committed brokers should have have their stake reallocated to them

[patriacaelum]

With the change specified above, there is no time limit for the "Fundraising" phase. It can be infinitely long until the owner chooses to cancel the proposal.

Should there be a specified time limit for the "Fundraising" phase before the proposal is forced to cancel?