- disabled use of headermaps, so it can handle multiple headers with the same name (in different folders) properly
- enabled use of UnrealEd.h as a precompiled header, which makes indexing faster
[CL 2103393 by Michael Trepka in Main branch]
Add Runtime/Engine/Private as and Engine private include path
Rename Engine/Private/Materials/MaterialInstance.h to MaterialInstanceSupport.h because it was causing ambiguities
Move cpp files from Classes and Public into Private
#codereview steve.robb, Robert.Manuszewski, nick.penwarden
[CL 2078806 by James Golding in Main branch]