Currently, CTOR sorts the transactions after constructing the block. To ensure that the associated fees and sigops are sorted with it, they were wrapped into a single object and stored together in a vector. However, this means that the transactions must be then copied into a CBlock->vtx array afterwards.

This task represents fixing that. There are two possible fixed:

Revert the commit associated with the change in D2047, and use std::sort on a zipped container.

Or:

Make CBlockTemplate inherit from CBlockHeader and fix IncrementExtraNonce to properly handle the CBlockTemplate version of the transaction list. This is possible as well, since once mined the RPC accepts a CBlock properly anyways. IncrementExtraNonce is only used in the generate rpc call, and is used to also produce a correct merkle root.