#change All headers in Classes, Public and Private are treated as candidates for UHT.
#change All candidate headers are scraped for the presence of a UCLASS, USTRUCT, UENUM, UINTERFACE and UDELEGATE at the start of a line and are only passed to UHT if one of these is present.
#fix Removed UENUMs from various games which were picked up as false positives by UBT but were never intended to be parsed by UHT.
#fix SocketSubsystem.h was including itself.
#codereview robert.manuszewski
[CL 2058796 by Steve Robb in Main branch]
