feature request: function to group by genotype

[antonkulaga]

The major headache that we had with oakvar/opencravat was that we do not see the exact genotype per raw to see if I am homo or heterozygous at some position. I understand that they way annotators work is that the get a value on some positions and have to provide output as fields and that for analyziz of more complex things we can use reporters.
However, knowing the exact genotype is so needed feature that I believe there should be some very fast oakvar function that we should be able to call for that to avoid reimplementing it in our reporters.
On top of it, I would also think it can be of use to have an additional type of annotators that get positions on both chromosomes when annotating.

[rkimoakbioinformatics]

@antonkulaga I understand the need and the pain. I am thinking about a solution. The problem is related to a bigger question which touches the core architecture of OakVar. It shouldn't take that long.