There are many instances we accidentally merge pull requests with outstanding warnings, as the fact warnings exists is not made obvious. This forces all `inspectcode` warnings to an error level.
This class hierarchy was originally when we had different HUDs for rulesets, but this is no longer the case. Skins will be able to build off the base (new) HUDOverlay without issue, so there is no real need for the abstract class for now.
We can add it back if a need for it arises; for the moment I'd like to avoid as many Standard* classes as possible.