[renderer] removed exposure option as it wasn't used (legacy) and it'…

…s instead controlled via the camera properties

[shaders] removed one binding slot

[font] all text entries now use a single vertex and index vector

[editor] introduction and sponsor windows will now appear in the cent…

…er of the viewport and on top of all other windows

[world] fixed an issue where upon re-loading worlds, the game would n…

…ot shutdown

[editor] exposed world window button so that you can bring up the wor…

…ld list and load any world at any moment, not having to restart the engine

[display] fixed an issue where the luminance would be detected correc…

…tly but logged as zero in the console

[worlds] in the forest world, the car will not be optimised using mes…

…hoptimizer, this is because there is no performance loss and the car looks much better

[font] fixed an issue where the index and vertex buffers could be rea…

…d by the GPU while CPU was writting to them causing glitches (this fixes most of the on-screen text issues, but another one remains)

[font] possibe fix for on-screen text not aligning correctly with dif…

…ferent monitor DPIs