* Blood had this right. It makes sense that the horizon be based around as it's easier to work with.
* Removed all associated game math to deduct default horizon of 100 when doing weapon zvel etc, meaning actual horizon can just be used.
* Re-did return to center function to work on the already converted pitch. Return speed should be 1:1 with previous code.
* use static_assert directly. Raze is C++17, no need for that macro shit.
* removed CONSTEXPR - I seriously fail to see the use here, many of the functions marked as CONSTEXPR cannot possibly even be constant evaluated so the declaration makes no sense. Removed most of these and replaced the valid ones with the official constexpr keyword.
* got rid of EDUKE_PREDICT_FALSE - this makes zero sense in script parsing code, at best it will save a few microseconds. Clean code wins.
* replaced Blrintf with xs_CRoundToInt. Shitty name is shitty name, even if derived from POSIX.
* replaced Bstr*casecmp with str*icmp. As these get defined in the CMake project based on actual compiler checks they are preferable here.
* removed lots of other stuff that is not needed with a minimum compiler requirement of C++17.
This removes the special handling for it in the main loop.
Some functions and variables in the kill and secret managers were also given more meaningful names.
Fixes#313
* Remove fix16.h/cpp and utilise library from m_fixed.h.
* Extend m_fixed.h with two inline functions for int to/from float operations.
* Replace fix16_floor operations with those from xs_Float.h
* Replace multiple Q16.16 conversions from 0 to just be 0.
* Replaced all found in-game bit-shifts and multiplications/divisions with inline functions from m_fixed.h
* Replaced many casts of FRACUNIT as double in SW's panel.cpp as it is converted to double by way of type promotion.
* Fixed missed precision fixes in SW's panel.cpp where some types weren't declared correctly.
* Replaced 100+ `Cos()/Sin() >> 16` operations for Blood with inline functions `CosScale16()/SinScale16()`.
Whatever this was for it made that thing extremely unwieldy.
With these merged the resulting structure doesn't look much different from Duke's anymore.
* Remove cast of int on `gFrameClock` since gFrameClock is now just an int.
* Remove unused `gFrameTicks`.
* Remove unused `gFrameRate`.
* Rename `gFrame` to `gFrameCount` so it's easier to search and distinguish from `gFrameClock` without relying on regex.
Avoid passing this anywhere in the client code. It should only be set right before rendering the 3D view and the only code using the base palette should be the 3D renderer and hud_drawsprite.
Also make the palette override CVARs 3D view only in debug mode.
- delete some voxel code that's software rendering only.
- apply Big Endian byte swapping for SFXs, as well, now that this no longer involves hacking the file system cache.
