Unit Equivalence

Composition table, yielding a normal-form according to https://github.com/unitsofmeasurement/unit-api/issues/89

NormalFormOrder	Composition	POWER	RATIONAL	MULTIPLY	PI	ADD	LOG	EXP
1	POWER	If same base → POWER, Else → LBO	RATIONAL	NFO	NFO	COMP	COMP	COMP
2	RATIONAL	#	RATIONAL	NFO	NFO	COMP	COMP	COMP
4	MULTIPLY	#	#	MULTIPLY	NFO	COMP	COMP	COMP
3	PI	#	#	#	PI	COMP	COMP	COMP
5	ADD	#	#	#	#	ADD	COMP	COMP
6	LOG	#	#	#	#	#	COMP	ID
7	EXP	#	#	#	#	#	#	COMP

# ... Omitted due to symmetry typeOf(a ○ b) ≡ typeOf(b ○ a)

ID ... IDENTITY POWER ... PowersOfIntConverter RATIONAL ... RationalConverter MULTIPLY ... MultiplyConverter ADD ... AddConverter LOG ... LogConverter EXP ... ExpConverter PI ... PowersOfPiConverter

COMP ... composition (a, b) -> a ○ b LBO ... composition with order (lower base first) (a, b) -> sort(a, b).first ○ sort(a, b).last NFO ... composition with order (lower normal-form-order first) (a, b) -> sort(a, b).first ○ sort(a, b).last