make various getter and pure-math methods clearscope, and where applicable, const

Original PR: https://github.com/coelckers/gzdoom/pull/532

Status of the original PR

1. Actor
- [already in] deltaangle
- [already in] absangle
- [already in] AngleToVector
- [already in] RotateVector
- [already in] Normalize180
- [already in] BobSin
- [already in] GetDefaultSpeed
- [this PR] GetBobOffset
- [this PR] InStateSequence
- [already in] FindState
- [already in] GetDropItems
- [this PR] DistanceBySpeed
- [this PR] AccuracyFactor
- [not in original PR, for PlayerInfo.isTotallyFrozen] isFrozen

2. PlayerInfo
- [this PR] GetUserName
- [this PR] GetColor
- [this PR] GetDisplayColor
- [this PR] GetColorSet
- [this PR] GetPlayerClassNum
- [this PR] GetSkin
- [this PR] GetNeverSwitch
- [this PR] GetGender
- [this PR] GetTeam
- [this PR] GetAutoaim
- [this PR] GetNoAutostartMap
- [this PR] GetClassicFlight
- [this PR] IsTotallyFrozen

3. C++ methods, to match ZScript:

- [scriptified] AActor::AccuracyFactor() to Actor.AccuracyFactor
- [this PR] AActor::DistanceBySpeed(AActor *, double) — it is a combination of getter and pure math
- [this PR] AActor::Distance2D(AActor *, bool) — called by DistanceBySpeed
- [this PR] AActor::Distance2D(AActor *, double, double, bool) — called by DistanceBySpeed
- [not in original PR, for PlayerInfo.isTotallyFrozen] AActor::isFrozen

# Conflicts:
#	src/actor.h
#	src/actorinlines.h

src/actor.h

@@ -850,7 +850,7 @@ public:
 		return (Pos().XY() - otherpos).LengthSquared();
 	}
 
-	double Distance2D(AActor *other, bool absolute = false)
+	double Distance2D(AActor *other, bool absolute = false) const
 	{
 		DVector2 otherpos = absolute ? other->Pos() : other->PosRelative(this);
 		return (Pos().XY() - otherpos).Length();
@@ -861,7 +861,7 @@ public:
 		return DVector2(X() - x, Y() - y).Length();
 	}
 
-	double Distance2D(AActor *other, double xadd, double yadd, bool absolute = false)
+	double Distance2D(AActor *other, double xadd, double yadd, bool absolute = false) const
 	{
 		DVector3 otherpos = absolute ? other->Pos() : other->PosRelative(this);
 		return DVector2(X() - otherpos.X + xadd, Y() - otherpos.Y + yadd).Length();
@@ -1490,7 +1490,7 @@ public:
 
 	// This is used by many vertical velocity calculations.
 	// Better have it in one place, if something needs to be changed about the formula.
-	double DistanceBySpeed(AActor *dest, double speed)
+	double DistanceBySpeed(AActor *dest, double speed) const
 	{
 		return MAX(1., Distance2D(dest) / speed);
 	}
@@ -1500,7 +1500,7 @@ public:
 	void DeleteAttachedLights();
 	static void DeleteAllAttachedLights();
 	static void RecreateAllAttachedLights();
-	bool isFrozen();
+	bool isFrozen() const;
 
 	bool				hasmodel;
 };

src/actorinlines.h

@@ -95,7 +95,7 @@ inline double AActor::AttackOffset(double offset)
 
 }
 
-inline bool AActor::isFrozen()
+inline bool AActor::isFrozen() const
 {
 	if (!(flags5 & MF5_NOTIMEFREEZE))
 	{

wadsrc/static/zscript/actors/actor.zs

@@ -450,7 +450,7 @@ class Actor : Thinker native
 		return sin(fb * (180./32)) * 8;
 	}
 
-	native bool isFrozen();
+	native clearscope bool isFrozen() const;
 	virtual native void BeginPlay();
 	virtual native void Activate(Actor activator);
 	virtual native void Deactivate(Actor activator);
@@ -602,7 +602,7 @@ class Actor : Thinker native
 		
 	native clearscope string GetTag(string defstr = "") const;
 	native void SetTag(string defstr = "");
-	native double GetBobOffset(double frac = 0);
+	native clearscope double GetBobOffset(double frac = 0) const;
 	native void ClearCounters();
 	native bool GiveBody (int num, int max=0);
 	native bool HitFloor();
@@ -698,7 +698,7 @@ class Actor : Thinker native
 	native void FindFloorCeiling(int flags = 0);
 	native double, double GetFriction();
 	native bool, Actor TestMobjZ(bool quick = false);
-	native static bool InStateSequence(State newstate, State basestate);
+	native clearscope static bool InStateSequence(State newstate, State basestate);
 	
 	bool TryWalk ()
 	{
@@ -746,7 +746,7 @@ class Actor : Thinker native
 	native bool LookForEnemies(bool allaround, LookExParams params = null);
 	native bool LookForPlayers(bool allaround, LookExParams params = null);
 	native bool TeleportMove(Vector3 pos, bool telefrag, bool modifyactor = true);
-	native double DistanceBySpeed(Actor other, double speed);
+	native clearscope double DistanceBySpeed(Actor other, double speed) const;
 	native name GetSpecies();
 	native void PlayActiveSound();
 	native void Howl();
@@ -782,7 +782,7 @@ class Actor : Thinker native
 		return level.totaltime - SpawnTime;
 	}
 
-	double AccuracyFactor()
+	clearscope double AccuracyFactor() const
 	{
 		return 1. / (1 << (accuracy * 5 / 100));
 	}

wadsrc/static/zscript/actors/player/player.zs

@@ -2712,23 +2712,23 @@ struct PlayerInfo native play	// self is what internally is known as player_t
 	native void SetSubtitleNumber (int text, Sound sound_id = 0);
 	native bool Resurrect();
 
-	native String GetUserName() const;
-	native Color GetColor() const;
-	native Color GetDisplayColor() const;
-	native int GetColorSet() const;
-	native int GetPlayerClassNum() const;
-	native int GetSkin() const;
-	native bool GetNeverSwitch() const;
-	native int GetGender() const;
-	native int GetTeam() const;
-	native float GetAutoaim() const;
-	native bool GetNoAutostartMap() const;
+	native clearscope String GetUserName() const;
+	native clearscope Color GetColor() const;
+	native clearscope Color GetDisplayColor() const;
+	native clearscope int GetColorSet() const;
+	native clearscope int GetPlayerClassNum() const;
+	native clearscope int GetSkin() const;
+	native clearscope bool GetNeverSwitch() const;
+	native clearscope int GetGender() const;
+	native clearscope int GetTeam() const;
+	native clearscope float GetAutoaim() const;
+	native clearscope bool GetNoAutostartMap() const;
 	native double GetWBobSpeed() const;
 	native double GetWBobFire() const;
 	native double GetMoveBob() const;
 	native double GetStillBob() const;
 	native void SetFOV(float fov);
-	native bool GetClassicFlight() const;
+	native clearscope bool GetClassicFlight() const;
 	native void SendPitchLimits();
 	native clearscope bool HasWeaponsInSlot(int slot) const;
 
@@ -2765,7 +2765,7 @@ struct PlayerInfo native play	// self is what internally is known as player_t
 		if (mo) mo.BringUpWeapon();
 	}
 	
-	bool IsTotallyFrozen()
+	clearscope bool IsTotallyFrozen() const
 	{
 		return
 			gamestate == GS_TITLELEVEL ||