BEAM JSON benchmarks

## DecodeBench
benchmark name           iterations   average time 
decode (small) (jiffy)       500000   117.63 µs/op
decode (small) (jsone)       200000   199.21 µs/op
decode (small) (tiny)        200000   216.86 µs/op
decode (small) (poison)      100000   225.53 µs/op
decode (small) (jason)       100000   228.00 µs/op
decode (small) (jsx)         100000   297.11 µs/op
decode (large) (jiffy)           50   612494.88 µs/op
decode (large) (jason)           50   981436.54 µs/op
decode (large) (jsone)           50   1133023.84 µs/op
decode (large) (poison)          20   1694305.75 µs/op
decode (large) (tiny)            20   1714289.25 µs/op
decode (large) (jsx)             20   1940736.05 µs/op
## EncodeBench
benchmark name           iterations   average time 
encode (small) (jiffy)       500000   77.03 µs/op
encode (small) (jason)       500000   143.08 µs/op
encode (small) (tiny)        200000   188.31 µs/op
encode (small) (poison)      200000   195.31 µs/op
encode (small) (jsone)       100000   264.95 µs/op
encode (small) (jsx)         100000   418.21 µs/op
encode (large) (jiffy)          100   284801.12 µs/op
encode (large) (tiny)            50   768584.04 µs/op
encode (large) (poison)          50   853984.44 µs/op
encode (large) (jason)           20   1595538.70 µs/op
encode (large) (jsone)           10   2446723.70 µs/op
encode (large) (jsx)             10   2824412.60 µs/op