deletion: deletion searching
In HAP.ROR: Recursive Organizer (ROR)

function of searching for the next grouping given deleted SNPs

1	deletion(lib, lib.names, case.sub, ctl.sub, aic.now, dev.now, df.now, rank = FALSE, cut = -1, delete.snp = -1, ref = "NA", alpha = 0.05, step = 0)

`lib`	the alleles library contains allele sequences for those only appear in the case and control samples
`lib.names`	the corresponding names of the alleles
`case.sub`	case subjects, two columns for two haplotypes
`ctl.sub`	control subjects, two columns for two haplotypes
`aic.now`	aic for the current model
`dev.now`	deviance for the current model
`df.now`	degree of freedom for the current model
`rank`	numbers of pairs with top similarity scores to be investigate if FALSE, then deviance is calculated for the step-wise merger, then option "alpha" and "step" is used
`cut`	cutoff for similarity score to be consider, default is -1, means all scores above 0
`delete.snp`	a vector of position of deleted SNPs
`ref`	allele names for the reference level, the default reference level (ref="NA") is the most common allelels
`alpha`	family-wise error, used for deviance only
`step`	index for how many deletions have been carried so far