resolve deletion reporting bug
resolve deletion reporting bug

Report the base before the deletion and the deleted sequence as the
reference allele, as opposed to previous non-compliant implementation.

nh13/freebayes,godotgildor/freebayes,ekg/freebayes,gkno/freebayes,godotgildor/freebayes,gkno/freebayes,ekg/freebayes,gkno/freebayes,nh13/freebayes,nh13/freebayes,ekg/freebayes,godotgildor/freebayes,nh13/freebayes,gkno/freebayes,nh13/freebayes,ekg/freebayes,godotgildor/freebayes,ekg/freebayes,godotgildor/freebayes,gkno/freebayes