add a de-noising node merge command
Add additional test for subgraphs in each locus
fix debug output for range
fix so that subGraph check is only run when SVLocus is supposed to be in a valid state
further restrict public iface of SVLocus
tweak the edge function
fix range printer to reflect internal zero-indexed values, this will be
consisten with all other debug output
add new merge intersect function to prevent merging of noise nodes