Warning Cleanup

[zrax]

Greatly reduces the number of warnings (when enabled) for both GCC and MSVC builds.

[Hoikas]

I wonder if compilation times would be negatively affected on MSVC by simply dropping the #pragma hdrstops...

[zrax]

I wonder if compilation times would be negatively affected on MSVC by simply dropping the #pragma hdrstops...

On my machine (building in VC 2019 with msbuild /m:8 on an SSD), I see a clean build in ~3m50s with #pragma hdrstop and ~4m04s without it, so the difference is not significant for me. However, I don't know if the IDE builds in parallel by default, or how much different the results would be on a slower machine (or slower drives).

[Hoikas]

That seems acceptable to me - there are plenty of other low hanging build speedups available in header cleanups and unity builds.