* Paint is now the non-virtual entry point to OnPaint to support required pre/post functionality. Widgets override OnPaint as usual, but calls to tell a widget to paint should be "Paint" not "OnPaint".
* ArrangeChildren -> OnArrangeChildren. ArrangeChildren is now the non-virtual entry point for the same reason as Paint/OnPain.
* OnPaint and OnArrageChildren are now private so they are not accidentally called.
* Added Stats for Paint time and ArrangeChildren time.
#BUN
#codereview:nick.atamas,max.preussner
[CL 2086158 by Wes Hunt in Main branch]
#proj core
#branch UE4
#summary Rename Trunc, Round, Floor, Ceil to TruncToInt, RoundToInt, FloorToInt, CeilToInt. Added *ToFloat versions. Repeated for FGenericPlatformMath and all derived classes for all platforms wherever applicable. Corrected comment in Fractional and added Frac() which does HLSL-style fractional (x - floor(x)). Checked for compilation on all projects (with cooking levels wherever applicable). Didn't change Fractional to Frac, this will be done in second commit.
#codereview robert.manuszewski
[CL 2064306 by Mikolaj Sieluzycki in Main branch]
#TTP 314475 - k2: comment boxes within other comment boxes do not move if the outer most box is moved. Also, if two nested comment boxes are moved, the nodes within move 2x as much as they should (video)
#Branch UE4
#Proj GraphEditor, BehaviourTreeEditor
#Add SNodePanel::SNode::FNodeSet typedef for conveniance and clarity
#Change Changed SNodePanel::MoveTo to take an FNodeSet as an exclusion filter on the moved nodes, once moved nodes are appended into this set.
CodeReview Chris.Wood, Nick.Whiting
[CL 2064255 by Ben Cosh in Main branch]
