switched SequenceDB to use WeakValueDictionary for automatic garbage collection
switched SequenceDB to use WeakValueDictionary for automatic garbage collection

GenDataPro/pygr,theoryno3/pygr,cjlee112/pygr,RitwikGupta/pygr,ctb/pygr,cjlee112/pygr,cjlee112/pygr,GenDataPro/pygr,ctb/pygr,RitwikGupta/pygr,ctb/pygr,ctb/pygr,cjlee112/pygr,RitwikGupta/pygr,theoryno3/pygr,GenDataPro/pygr,theoryno3/pygr,ctb/pygr