Implement arithmetic operators with a macro #15

Job	Run time
List directories for parallelizing tests	12s
Check (stable)	15s
Check no_std	27s
Check (nightly)	1m 15s
Check Documentation	52s
Check Style	18s
Test assembly	8m 36s
Test (stable)	9m 13s
Test (nightly)	17m 56s
Test (cp6_782/)	5s
Test (mnt4_753/)	12s
Test (mnt6_753/)	11s
Test (./ed25519)	1m 0s
Test (./mnt6_298)	5m 48s
Test (./grumpkin)	1m 13s
Test (./ed_on_cp6_782)	1m 21s
Test (./ed_on_mnt4_753)	3m 48s
Test (./ed_on_bw6_761)	38s
Test (./bls12_381)	3m 14s
Test (./ed_on_bls12_381_bandersnatch)	1m 7s
Test (./ed_on_mnt4_298)	1m 5s
Test (./secq256k1)	56s
Test (./bn254)	2m 17s
Test (./mnt4_298)	3m 46s
Test (./secp256r1)	59s
Test (./vesta)	1m 16s
Test (./ed_on_bn254)	1m 2s
Test (./bw6_761)	4m 2s
Test (./curve25519)	1m 7s
Test (./pallas)	1m 12s
Test (./ed_on_bls12_377)	1m 14s
Test (./secp384r1)	1m 25s
Test (./secp256k1)	1m 5s
Test (./ed_on_bls12_381)	1m 18s
Test (./bls12_377)	4m 19s
Test (./bw6_767)	3m 59s
	1h 28m 43s

Provide feedback