Removes depency on WebBrowser project from Slate, it now depends on Slate instead.
Removed functions from Singleton interface that are no longer needed.
Get the Slate renderer when needed instead of keeping reference.
Added call to FTicker::Tick function in Slate viewer app so that Web Browser will continue to work.
[CL 2330030 by Matthew Griffin in Main branch]
Allow user to chose whether transparency is used for individual browser windows.
When browser viewport is resized or rendered with old size afterwards, made sure that the texture is copied row by row to avoid distortion.
Store size of viewport as an FIntPoint to avoid various casts that would be needed.
[CL 2321219 by Matthew Griffin in Main branch]
Web Browser project mostly exposes interfaces, hiding all of the CEF3 implementation and technically allowing us to slot in another web system if necessary. Normal process will be to request a browser window interface from the web browser singleton. There is also an implementation of ISlateViewport so that it can be displayed via an SViewport.
The UnrealCEFSubProcess executable is needed for CEF3 to run additional processes for rendering etc. I don't expect this to change very often so it should hopefully just be built once and distributed, since we can't currently specify a program dependency for other modules.
Added a CEF3Utils project to share .dll loading code between web browser and the separate sub process executable.
[CL 2317298 by Matthew Griffin in Main branch]
