CUDS specification and reference implementation

The existing Common Universal Data Structures (CUDS, https://github.com/simphony/osp-core, implemented in Python) is extended to support multiple features needed for large scale efficient semantic data exchange across geographical locations and platforms in a secure manner. The delivery will consist of an up-dated data structure specification for CUDS and extended with reference implementations for the languages and platforms needed by the showcases, i.e. a C and JavaScript implementation.