Merge pull request #12 from emiswelt/master

Key property
Switched key and value for DoubleModListNode and updated Datastore to not
automatically put all input into mods.
Fixed issue in experiment with key/values not being switched.
Fixed a deadlock by removing LocalMod.
Merge branch 'master' of https://github.com/twmarshall/tbd
Removed a debugging prinln and increased the akka timeout.
Introduced Iterators
Merge remote-tracking branch 'upstream/master'
Introduced Iterator