Strat writer life improvement: make regular reverts work and return arbitrary data after success

[adhusson]

Currently, Mangrove reads the 32 first bytes of returndata (let's say d) after makerExecute. If no revert and d = 0, the execution is considered a success; otherwise a failure.

We propose changing that to:

• If no revert, read the first 32 bytes of returndata. This matches the bytes32 returned according to the ... makerExecute returns (bytes32) signature. In addition, consider the execution a success.
• If revert, read the 69th to 100th bytes (included) of returndata. This matches the first 32 bytes of string str returned through, e.g. require(false,str). In addition, consider the execution a failure.

[espendk]

@adhusson Is this part of the changes you just merged?

[adhusson]

Yes! Done with 4afc124