Reverse-Z Pipeline

• Add a define option to switch the pipeline to reverse-Z mode
  • Flipped depth
  • Infinite far plane
  • Zero-to-one clip space
  • Enabled by default
• Improve shadow cascade system
  • No longer requires squared camera distance in shader, simplified glsl interface
  • Fixed circle artifact on cascade edges
  • Improved configurability with cascade split lambda in RenderScene
• Fix TAA Jitter extent
  • From [-1, 1] to [-0.5, 0.5]
  • Reduces jittering and blur
• Add imgui utils to glow-extras-debugging
  • Add dark and light ImGui "glow theme"
  • Enabled in viewer
• Add "Suppress" button to DebugOverlay
  • If suppressed, the overlay no longer becomes visible on new OpenGL errors
  • Only a call to ToggleVisibility (F10) un-suppresses the overlay
• Add viewport output settings to the pipeline
  • Use them for multiple subviews in the viewer in favor of a temporary fbo and blitting
• Minor fixes
  • Adjust outline normal threshold in viewer
  • Fix preprocessor condition for imgui presence