New view menu

[BlackYps]

Add a "View" Menu that contains grid overlays and alternative viewing modes.

• The center lines can now be toggled independently of the grid overlays
• The grid views have been reimplemented. Issues with the old grid views should be gone now.
• The center lines can now be toggled independently of the grid overlays
• New view modes are available:
  • Untextured, to check the lighting conditions
  • Layer Masks, to troubleshoot texture layers
  • Normals
  • Roughness, only for Terrain100 and Terrain200 shaders
  • Ambient Occlusion, for all shaders that use the Terrain Info Texture