Unshelved this merge from Stephan and then completed the merge with additional fixes and testing.
Hand fixed some WorldExp compile issues due to changes to OnPaint() signature.
#Integration
[CL 2245992 by Daniel Broder in Main branch]
There was a bug in setting affinity of a thread that assumed affinity from lookup table with key being a thread name. When names was appended with consecutive numbers (e.g. "RenderingThread 1") the mechanism failed. Refactored this to use special static consts describing affinity override'able by different platforms for different affinity types + possibility of setting affinity per thread.
#codereview Jaroslaw.Surowiec
[CL 2070197 by Jaroslaw Palczynski in Main branch]
#proj core
#branch UE4
#summary Remove all bAutoDeleteSelf and bAutoDeleteRunnable usage from the runnable.
#codereview Robert.Manuszewski
[CL 2070165 by Mikolaj Sieluzycki in Main branch]