virtual mouse control

[hydrojan]

@Stormwind;501432

I took a different route to 3D VR gaze input: I implemented basic gaze-to-actor-with-widget-component and widget-cursor-display in Blueprint, then made a GazeInput plugin using code adapted from SlateApplication’s input processing code. This way the gaze input works with all widgets as-is without the need to add new detection geometry or create new widget types.

I hope to clean it up and release the plugin and instructions in future, unless Epic beats me and releases similar functionality themselves.

Nice solution for mouse. But for leap motion not good actually.