WIP: ENH: Integration of CUDS using osp-core package

[flongford]

NOTE: this PR requires a local installation of osp-core>=3.3.2

Integration with CUDS-type ontologies is achieved using osp-core package. This PR expands upon the CUBAType attribute functionalities in order to allow for a simple python basic type and TraitType class lookup for a given CUBA key.

Consequently, we are now able to utilise powerful extended physical unit typing abilities provided by an ontology. We expect later extensions to expand upon this by integrating external software wrappers built around the osp-core ontology system.

Approaches #279

Change log:

• BDSS installation requires osp-core>=3.3.2 (expected to fail on Travis CI)
• New Ontology class, a subclass of TraitType, allowing for HasTraits subclasses to hold OntologyNamespace attributes
• New IOntologyRegistry class providing an interface between loaded osp-core ontologies and CUBAType objects
• New CUBATypeMixin class providing the ability to look up CUBA keys in a provided IOntologyRegistry
• CUBAType class now contains regex rules determined by osp-core
• New example TypeMCOStartEvent that is able to report variable trait type as well as name information

[flongford]

This implementation is not ideal, since we end up needing a registry system for CUBAType objects. This system should ultimately come from the ontology modules themselves (we don't want to redesign global state).

In which case, we should redefine the CUBAType class as a traits wrapper around OntologyAttribute, which already has a reference to the ontology in its module path. However, this will break any existing plugin objects using simple strings as DataValue.type objects.

[flongford]

Note: the CUBATypeMixin class should also probably be inherited by DataValue