What is spline in notITG???

	tl;dr - list of points on the playfield (measured in time away from receptors, in beats)
	paired up with a list of mod values for those points.

	Arrow properties that can be spline'd:
		X
		Y
		Z
		RotationX
		RotationY
		RotationZ
		Size
		Stealth
		Skew
	
	
	
	
How to Apply:

	Call it on Playfield.
	
	local P1 = SCREENMAN:GetTopScreen():GetChild('PlayerP1');
	
	P1:SetXSpline(
		which,
		column(-1 for all columns),
		mod percentage,
		offset (distance from recep in beats)
		activation speed (set -1 for instant)
	)
	
	due to the way this is set up, it's easy to apply large amounts of splines using a for loop.
	
	There is a limit of 40 splines per property per column.
	
	
	
	
	
How to Reset all:
	
	Apply mod "spline"..axis.."reset" or "spline"..col..axis.."reset"
	(axes are x,y,z,rotx,roty,rotz,size,stealth,skew)
		
	It activates immediately and instantly kills all splines in that column and axis
	
	
	
	
Quirks of splines:

	Holds suck at splining in default ITG.
	I made a version of the hold renderer that plays much nicer with splines.
	To use, activate the mod "spiralholds".
	
	If you activate 50% flip and 50% reverse, you can have much more direct control of the motion path
	of arrows using splines.
	
	splines have multiple different "join" types.
	To change the join type, use "spline"..axis.."type", where axis is one of the aforementioned axes.
		
		splinetype = 0
			Default, linear splines. Connected with straight lines.
			
		splinetype > 0 && splinetype < 100
			Cosine connected splines.
			
		splinetype > 100
			Cubic splines (bezier joining the points. useful for smooth links using few points.)
			
	Certain things will cause splines to truncate (the rest will be ignored after a point)
	
		if a nil spline is encountered (i.e. both offset and mod percentage == 0, optimization step)
		offset of spline n+1 <= offset of spline n - so remember to have splines always sorted in ascending offset order
	
	
	In XYZ mod percentage property, 100% is equal to ARROW_SIZE, which is 64 pixels by default in ITG.
	In RotationX, Y and Z, 628.3% is equal to 360 degrees (2*math.pi*100)
	Size uses the same formulae as Mini and Tiny (200% = 0 zoom)
	Stealth is just stealth
	Trying to get precise values using skew is like trying to count powder.