assorted fixes/tweaks for blocked sampling
assorted fixes/tweaks for blocked sampling

dedupeio/dedupe,01-/dedupe,davidkunio/dedupe,dedupeio/dedupe,nmiranda/dedupe,01-/dedupe,pombredanne/dedupe,datamade/dedupe,neozhangthe1/dedupe,tfmorris/dedupe,pombredanne/dedupe,nmiranda/dedupe,neozhangthe1/dedupe,davidkunio/dedupe,datamade/dedupe,tfmorris/dedupe