Add Ramp brush and other fixes

[JamesTKhan]

• Add a Ramp Brush to terrain editor to allow creating a ramp from brush position to a designated end point
• Smooth tool was not applying brush shapes, fixed so that it now does
• Add Vector2 and Vecto3 Pools to MathUtils
• Add very simple approach to hiding terrain brushes like on ramp tab
• Move unnecessary matrix/vector math out of loops in brush methods

Ramp:

2023-05-12.16-02-05.mp4

Smooth Brush fix:

2023-05-12.16-03-32.mp4