* Struct made up of binangle class units.
* Create signed clone of binangle for use with look_ang and rotscrnang.
* Append currently outgoing function names with `2` at the end to avoid conflict.
* Started with the most complicated game first.
* Struct made up of fixedhoriz class units.
* Append currently outgoing function names with `2` at the end to avoid conflict.
* 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.
* Need SW's input helpers available for Blood but therefore also need an angle delta function that does not seem to exist in Blood.
* Realise that gamecontrol.h/cpp might not be the most appropriate place, but it's a shared location and these will go into binaryangle.h when its utilisation can be more realised.
* Because SW's logic was reversed, in that param #1 was the new angle and param #2 was the current, all calls have been reversed.
* By happenstance, also fixes an issue with multiple 180° turns in quick succession.
