Consider using `:erlang.phash2/1` as the hash function

[Tangui]

If requirements are met, consider using :erlang.phash2/1 as the hash function which works on any erlang term.

It allows removing the Murmur dependency.

Note that it doesn't have a uniform output:

iex(9)> :erlang.phash2(:a)              
97
iex(10)> :erlang.phash2(:b)          
98

Not sure whether it's a problem or not.

[Derek Kraan]

Actually ... it might even be an advantage ... The resulting merkle tree would be denser than if you used a hash function that distributed hashes evenly.

[Derek Kraan]

Turns out :erlang.phash2 is about twice as fast according to my benchmarks... Thanks for the suggestion! 🎉