No longer using numpy.random because numpy does awful things to CPU affinity.
Cosmetic change.
bla
Some changes to the way messages are processed.

+ Now "discovered_resources" is simply "discovered" since it's no longer
restricted to resources.
+ The discovered data is now processed recursively.
+ Discovered data is only sent to plugins if completely new. Otherwise
it's ignored, to prevent accidental corruption when merging.
+ Instead of expecting and sending a dummy ACK for each dropped packet, we
now send a single ACK after the targets. This should speed things up a
little by avoiding unnecessary ACKs.
+ Added discovered IPs to Domain.