Handle infinite data with finite representations.

[fsvieira]

Currently there are some tests with infinite data, they stop because the zebradb-core allows to put a limit on branch depth creation.

For example natural numbers are infinite, one of the definitions can be (nat 0) (nat (nat 'x)) witch are
infinite, the idea is to make an finite representation something like (nat (nat 'x=[0 | (nat 'x)]).