* Remove some extern'd CVARs that didn't need externing.
* Change `player_struct::centeringView()` bool into proper method to handle the operation.
* Operation now properly unsets `SB_CENTERVIEW` if conditions aren't met instead of relying on implied behaviour from the rest of the playsim.
* Initially figured I could just use the sign of the angle adjustment, but the vehicle code makes left/right reversals that necessitate using the flags for this.
* Kept the workflow identical to the old setup in the other commits, but does not seem necessary and all it does is make the speed one tic behind where it would be otherwise.
* Back in 2020, I was trying to tidy stuff up and had no idea about network awareness, etc.
* The original game misused network bits here, however I don't see why the player's angle can't just be tested for signedness. Again, something I didn't see way back when...
* Back in 2020, I was trying to tidy stuff up and had no idea about network awareness, etc.
* We must continue the misuse of network bits like the original game did to make sure the RRRA vehicles are network aware.
* Back in 2020, I was trying to tidy stuff up and had no idea about network awareness, etc.
* The original game misused network bits here, however I don't see why the player's angle can't just be tested for signedness. Something I didn't see way back when...
* The original game spawning the player's sprite/actor would set the sprite's pos with the Z matching the player's, which had a height offset already applied.
* This baked in height offset was carried through up until the `SetActor()` call in `processinput()`, where the original game would then strip off `gs.playerheight`.
* This baked in height offset within the actor is critical on the first tic for pre-activated elevators on level spawn to function right, such as E1L2 and E2L3.
* Properly setting the player actor's Z immediately after the initial `getzrange()` call, but before other functions like `movement()`, etc further down in `processinput()` is the best spot.
* Fixes#870.
All map geometry npw uses texture IDs and no longer depends on Build's tile system.
(What's missing is a new map format, though, but this was a necessary prerequisite to make that worthwile...)
That's the developer commentary icon in World Tour, the deactivation switch for the chicken processing plant in RR and one shootable alarm bell in RRRA.
