add filtering on Z0, Z1, Z2
add filtering on Z0, Z1, Z2

Please do not rely on this; it's horrible ad-hockery that
needs to be replaced soon.

mpieva/samtools-patched,udo-stenzel/samtools-patched,udo-stenzel/samtools-patched,mpieva/samtools-patched,mpieva/samtools-patched,mpieva/samtools-patched,udo-stenzel/samtools-patched,mpieva/samtools-patched,udo-stenzel/samtools-patched,udo-stenzel/samtools-patched