With the exception of isWorldTour, isPlutoPak and isShareware when playing Duke these are always constant and this way can be used to completely eliminate unneeded code.
This not only matches its use in CON but seems to be used as a counter in most other places as well.
The main reason is to improve readability of CON to ZScript conversions.
As soon as default init for CON gets in this won't work right anymore - these must come last, not first.
This commit contains all the trivial cases with no inheritance concerns.
