#jira UE-11567 - In Use By Level Filter disabled when renaming asset
#jira UE-11569 - Moving an asset In Use By Level is enabled will make it not visible in filter
#codereview Matt.Kuhlenschmidt
[CL 2508158 by Richard TalbotWatkin in Main branch]
https://github.com/EpicGames/UnrealEngine/pull/946
I have gone through these changes and verified that whatever behavior change they cause could only be an improvement (generally they just prevent possible access to nullptrs, but there are also some style corrections). A separate changelist is being prepared that includes changes that could unintentionally caues behavior change for the worse.
[CL 2486801 by Dan Oconnor in Main branch]
#UE4 Renaming assets no longer attempts to load all their referencers. This happens earlier in the rename process and is corretly skipped if being referenced by a map or already checked into SCC.
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Integrated using branch Ue4-To-UE4-Fortnite-Simple (reversed) of change#2401575 by Bob.Tellez on 2015/01/08 21:19:31.
[CL 2401576 by Bob Tellez in Main branch]
#ttp 348063 - Crash moving files in Content Browser
#branch UE4
#proj Developer.AssetTools, Editor.ContentBrowser, Editor.PackagesDialog, Editor.UnrealEd
[CL 2328547 by Richard TalbotWatkin in Main branch]
Removed UENUM() from EMyTownBuildingsWidgetSorting and EMyFortRatingStarSize to fix compile issues and because UENUM() was unnecessary.
Also made hand-fix to UAIHotSpotRenderingComponent by removing HeaderGroup (obsolete).
Did not merge TRV_HAF_Outer_012_lower_border or TRV_HAF_Outer_030 umaps due to conflicts and based on advice from Stefan.
[CL 2060490 by Daniel Broder in Main branch]
