Fix get examples for diploid case

[szhan]

Fix #43

[szhan]

For now, it should raise an error when using the including ancestors option, because it is not correctly implemented yet.

[szhan]

I suspect that there is a bug as well, because the tests fail when a query has only MISSING, which should work.

[szhan]

It turns out that there is no bug as suspected above. It's just that one of the tests ran into a pathological case where both the mutation rate and recombination rate are very low (1e-6) and there is no normalisation, resulting in comparisons of extremely low log-likelihood values (nearly 1e-15).

As discussed with @astheeggeggs , one way around this is to run all the tests on the non-extreme parameter value combinations, so as to avoid comparisons of extremely low LL values; then, proceed to run the tests on the extreme parameter value combinations with normalisation.

[szhan]

The above should be fixed in a separate issue.

[szhan]

Also, for now, the tests are not covering cases when the ref. panel contains partial ancestral haplotypes with NONCOPY.