* Moved Slate.h into SlateBasics.h and began shifting less commonly used headers into SlateExtras.h.
* Slate.h now simply includes SlateBasics.h and SlateExtras.h.
* Slate.h includes a deprecated warning now to indicate that SlateBasics.h + specific includes should be used instead.
* Moved dozens of inlined functions using Slate widgets into .cpp files to avoid header dependencies.
* All code samples now include SlateBasics.h and SlateExtras.h so future shifts will not break most those projects, but not trigger the deprecation warning of including Slate.h.
#BUN
[CL 2329610 by Wes Hunt in Main branch]
- Clean up FDragConnection construction and add a factory function in SGraphPin to extend it for some pins
- Clean up arguments to FOnGetContextMenuFor in SGraphPanel
- Various modifications to SGraphPin to permit implementation of wire knots/reroute nodes
#codereview nick.whiting
[CL 2074801 by Michael Noland in Main branch]
#ttp 327253 - ANIM: DEV: Create a nice workflow for editing animation overrides in derived anim blueprints
#branch UE4
[CL 2060901 by Benn Gallagher in Main branch]
