TEI concepts

[twagoo]

Applying clarin-eric/VLO#63 to VLO-mapping project since facetConcepts.xml that has the changes has moved into this project.

[twagoo]

Reposting Menzo's alternative proposal:

We could try out the <acceptableContext> construct. This allows to say which ConceptLinks on enclosing components are acceptable. And also allow empty context. A problem can be that there are other contextual ConceptLinks that we don't know yet. They have to be explicitly accepted, or we have to go in the code and make the context white/black list potentially more concept specific:
<facetConcept><concept><acceptableContext><concept/></><rejectableContext><concept/></></></>

[twagoo]

Will not attempt the < acceptableContext> approach for the upcoming release. This is now covered by issue #3 and can be picked up later in this project.