Speed improvements
Speed improvements

replace multiple filters by a single and_ filter
use uuids instead of objects
replace transmission state with status
rewrite Network.transmissions()
rewrite Node.is_connected()
rewrite Node.transmissions()

Dallinger/Dallinger,Dallinger/Dallinger,suchow/Wallace,berkeley-cocosci/Wallace,berkeley-cocosci/Wallace,jcpeterson/Dallinger,jcpeterson/Dallinger,jcpeterson/Dallinger,Dallinger/Dallinger,jcpeterson/Dallinger,jcpeterson/Dallinger,Dallinger/Dallinger,suchow/Wallace,berkeley-cocosci/Wallace,suchow/Wallace,Dallinger/Dallinger