Zstd codecs

This library registers zstd compression codecs as zstd_1, ..., zstd_22. Fast levels are also registered as zstd_fast_1, ..., zstd_fast_7.

Measured codec performance on every level. Values below are provided just for reference, exact numbers may vary depending on CPU model and type of data being compressed.

Codec	Comp. Ratio	Comp. Speed (MBps)	Decomp. Speed (MBps)
lz4	0.5876	913	4100
zstd_fast_7	0.5783	1066	2887
zstd_fast_6	0.5733	1050	2870
zstd_fast_5	0.5528	942	2594
zstd_fast_4	0.5529	918	2659
zstd_fast_3	0.5408	885	2519
zstd_fast_2	0.5132	769	2374
zstd_fast_1	0.5119	707	2386
zstd_1	0.4691	690	1692
zstd_2	0.4083	467	1496
zstd_3	0.3505	358	1801
zstd_4	0.3356	310	1932
zstd_5	0.3175	218	1832
zstd_6	0.3168	173	1920
zstd_7	0.3081	149	1965
zstd_8	0.3077	125	2005
zstd_9	0.272	128	2179
zstd_10	0.2693	98.5	2228
zstd_11	0.2684	78.6	2185
zstd_12	0.2682	71.1	2231
zstd_13	0.2687	27.8	2102
zstd_14	0.2676	24	2024
zstd_15	0.2663	18.8	2225
zstd_16	0.257	15.2	2093
zstd_17	0.2521	12.3	2072
zstd_18	0.241	9.68	1696
zstd_19	0.2395	7.97	1709
zstd_20	0.2337	6.26	1520
zstd_21	0.2255	5.22	1442
zstd_22	0.2037	3.88	1490