Add NSD Validation

[dlabordus]

Remark:

First step is to check the status of the NsdValidator in RiseClipse. 
It looks like it's not yet implemented. 
See https://github.com/riseclipse/riseclipse-validator-scl2003, class 'NsdEObjectValidator' in package 'nsd' of the project.

RiseClipse also has the possiblity to use NSD Files to validate SCL Files.
There is a Metamodel that can be used to validate with NSD Files (https://github.com/riseclipse/riseclipse-metamodel-nsd2016)
And there is a class 'NsdValidator' there can be rebuild to be used in CoMPAS, like the class 'OCLValidator' (in CoMPAS called 'OclFileLoader').

[dlabordus]

We need to ask Dominique Marcadet (RiseClipse) if the implementation is working, during meeting it was a little bit unclear for me. And also ask why the NSD files are used, because we then will have XSD, OCL Files and NCD Files. Is this really needed?