* Further review of this should be considered as the use of sintable[] for nCos was actually sine and the use of sintable[] for nSin was actually cosine. Preserved math despite the variable names.
* 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.
* For Blood/SW, exposes `SB_LOOK_LEFT`/`SB_LOOK_RIGHT` to games, hooking up `q16look_ang` and `q16rotscrnang` within.
* For SW, use Duke & Blood's return to center function and remove `PF_TURN_180` bit.
* For RR, replace a few misused bits with some bools inside of `player_struct`.
* Since bulk of functionality is sourced from Duke (30Hz), apply proper scaling so SW speed matches (40Hz).
* For Duke/SW, we continually apply `SB_CENTERVIEW` only if it was previously a toggled action, similar to Blood.
* For SW, we remove two SW-specific bits (`PF_LOCK_HORIZ` and `PF_LOOKING`) that are no longer needed.
* For Duke, we remove `return_to_center` and just use the `SB_CENTERVIEW` action bit as required.
* For `sethorizon()`, feature set and adjustment speeds are an averaged out accumulation across Duke/SW:
** GameTicRate is factored in for adjustment decisions to provide consistency for SW being the faster game.
** Adjustment amounts are half way between Duke/SW.
* Horizon now standardised on 100 like the other games.
* Need to determine where/why/how the player's horizon is starting out at 0 and get it to init at 100 like the other games.
* Changed config so `cl_interpolate` bool doesn't apply to player's overall movement. While it might be handy for debugging moving sector objects, I see no valid reason why there'd be a need to ever un-interpolate the player's position.
* 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.
They need to be reset when level data gets set because the current value is used as base.
It was most easily observed at the start of the first level where the grave only would open after a lengthy delay - which was the play time of the last level being played.
