This is needed to allow 2D to fully make use of 3D effects (e.g. glow), and can be used to substantially improve quality of 2D rendering at the cost of performance
Additionally, the 2D rendering pipeline is done in linear space (we skip linear_to_srgb conversion in 3D tonemapping) so the entire Viewport can be kept linear.
This is necessary for proper HDR screen support in the future.
Fixes include using proper depth buffer format in 3D (this had previously been fixed already but the changes were lost in a rebase), Remove unused lighting and shadowing code in 2D, and update 2D UBOs using glBufferSubData so that they remain the appropriate size.
