Reimbursements

[marshabl]

Here is an approach to moving from reverts -> returns, using the preOpsCall as an example

Changes:

• Update Context in locktypes and safetylocks to include an array of Reimbursement structs (defined in locktypes)
• update escrow to capture the gasUsed in preOpsWrapper -> this captures the gas regardless of whether it fails or succeeds because we need to reimburse either way
• create a new Reimbursement struct with the gasUsed and the reimburser
• push it into the ctx.reimbursements
• on revert, we return instead of revert
• then in atlas.sol -> execute, we have access to ctx.reimbursements (whether failed or succeeded) and we can call settle in there with the ctx so it can do the transfers

ToDo:

• Update the rest of the hooks to capture reimbursements and return instead of revert