* Filtering by IU event type.
* Description of sniffer arguments after startup now prettier.

Manually integrated the following changes from b8466a (master 2015-11-13)

- Blackboard classes by hvanwelbergen
- Blackboard test by hvanwelbergen
- Payload merge fix by hvanwelbergen
- rsb Buffer fix (by myself) copied but inactive (not needed atm?)

Please refer to the logs of the legacy-str branch for a full history
of the respective changes.

Sniffer: only display quotes for string-type payload values
Injector: using unicode() and catching errors

ipaaca-iu-sniffer optionally takes a list of category arguments
(if not specified, it still listens for everything).
ipaaca-iu-injector needs to be provided with a category name
and, optionally, with key-value pairs for the payload, as such:
$ ipaaca-iu-injector  murmlfile  data  smile_3sec.us