Variable add

add: (rotationSecond: number, rotationFirst: number) => number

Composes the two D8 operations.

Taking ^ as reflection:

	E=0	S=2	W=4	N=6	E^=8	S^=10	W^=12	N^=14
E=0	E	S	W	N	E^	S^	W^	N^
S=2	S	W	N	E	S^	W^	N^	E^
W=4	W	N	E	S	W^	N^	E^	S^
N=6	N	E	S	W	N^	E^	S^	W^
E^=8	E^	N^	W^	S^	E	N	W	S
S^=10	S^	E^	N^	W^	S	E	N	W
W^=12	W^	S^	E^	N^	W	S	E	N
N^=14	N^	W^	S^	E^	N	W	S	E

[This is a Cayley table]https://en.wikipedia.org/wiki/Cayley_table

Type Declaration

- (rotationSecond: number, rotationFirst: number): number
- Parameters
  - rotationSecond: number
    Second operation, which is the row in the above cayley table.
  - rotationFirst: number
    First operation, which is the column in the above cayley table.
  Returns number
  Composed operation