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.

(This was sufficient for basic interoperation, e.g. DM<->realizer)

Made ipaaca-java compatible with ipaaca-python's JSON datatypes. No JSON support on the Java-side though.

fixed overlapping InputBuffer constructors and added BufferConfiguration and BufferConfigurationBuilder

Added ipaaca channel possibilities based on rsb scope. Also, deprecated incompatible InputBuffer constrcutors for non-container parameters for multiple categories, from cpp version

- fixed typo in ipaaca documentation

- made sure the initializer is only initialized once
- toString methods for payload and localIU

- Minor cleanups