Performance improvements

[SaveTheRbtz]

In this PR:

• Switch to faster hash

name          time/op
Murmur/1-8      2.68ns ± 1%
Murmur/4-8      3.45ns ± 1%
Murmur/8-8      4.70ns ± 0%
Murmur/16-8     6.19ns ± 0%
Murmur/32-8     10.6ns ± 0%
Murmur/50-8     16.3ns ± 2%
Murmur/500-8     202ns ± 0%
XXH3/1-8        2.53ns ± 2%
XXH3/4-8        2.51ns ± 2%
XXH3/8-8        2.45ns ± 1%
XXH3/16-8       2.35ns ± 1%
XXH3/32-8       3.16ns ± 0%
XXH3/50-8       4.87ns ± 5%
XXH3/500-8      38.6ns ± 1%

• Switch to faster sort

name      old time/op    new time/op    delta
Build        121ms ± 2%     101ms ± 3%  -16.14%  (p=0.000 n=10+10)
Table       36.7ns ± 2%    28.1ns ± 2%  -23.35%  (p=0.000 n=9+9)
TableMap    74.2ns ± 6%    63.9ns ± 3%  -13.95%  (p=0.000 n=10+9)

name      old alloc/op   new alloc/op   delta
Build       32.7MB ± 0%    32.7MB ± 0%   +0.02%  (p=0.000 n=7+9)
Table        0.00B          0.00B          ~     (all equal)
TableMap     0.00B          0.00B          ~     (all equal)

name      old allocs/op  new allocs/op  delta
Build         302k ± 0%      302k ± 0%   +0.07%  (p=0.000 n=10+10)
Table         0.00           0.00          ~     (all equal)
TableMap      0.00           0.00          ~     (all equal)

Ref: #3