query: support for output of IUPAC ambiguity codes
In a sense allow multisample and/or logic in -i/-e filtering.

For example, these haploid genotypes
    0 0
    1 0
    1 1

will pass the filtering as follows:
    -i 'GT  = "1"'      1 0, 1 1
    -i 'GT != "1"'      1 0, 0 0
    -e 'GT  = "1"'      0 0
    -e 'GT != "1"'      1 1