some initial, untested support for caching DAG graph lookups to speed up large pipelines
some initial, untested support for caching DAG graph lookups to speed up large pipelines

tucano/bpipe,tucano/bpipe,sb43/bpipe,vivovip/bpipe,sb43/bpipe,tucano/bpipe,vivovip/bpipe,sb43/bpipe,vivovip/bpipe