54011e7aa2 refactor: use CWallet const shared pointers when possible (Karl-Johan Alm)
96461989a2 refactor: const shared_ptrs (Karl-Johan Alm)
Pull request description:
```C++
const std::shared_ptr<CWallet> wallet = x;
```
means we can not do `wallet = y`, but we can totally do `wallet->DestructiveOperation()`, contrary to what that line looks like.
This PR
* introduces a new convention: always use const shared pointers to `CWallet`s (even when we mutate the pointed-to thing)
* uses `const shared_ptr<const CWallet>` everywhere where wallets are not modified
In the future, this should preferably apply to all shared pointers, not limited to just `CWallet`s.
Both of these serve the same purpose: to dispell the misconception that `const shared_ptr<X>` immutates `X`. It doesn't, and it's dangerous to leave this misconception as is, for obvious reasons.
ACKs for top commit:
theStack:
re-ACK 54011e7aa2
Tree-SHA512: 3bf4062fc821751be30770c6b4ead10a016847970f155a0a5156f304347d221b9830840030c2fbfba8cd1e282f4eda45f5b4107fe6df8138afdcb6c2e95a2836
baa9fc941c