no more need for SortedKey; hacked up a fix for store.go so it builds, sorry Teddy
removed SortedSeq struct entirely
made up SeqSorterOptions out of thin air
SeqSorterError added
extra paranoid error checking in SortSeq...
TrimEnds function for Seqs added. I feel like it should have been a modify-in-place method but not sure how to do that
added sweet sweet TODO to sortseq.go