Support for to_source_name_resolved in OCL Module

For some background, see here, but, roughly speaking, in OCL APIv2, it is no longer guaranteed that the to_concept_name property is always populated for concept mappings (including concept sets and concept answers). While we fixed the issue in the front-end in this commit, we need to fix this behaviour in the module as well.

To this end we need to ensure that the OclMapping class also gets the to_source_name_resolved property and we probably need to change the getToSourceName() function to something like this:

public String getToSourceName() {
	return toSourceName != null ? toSourceName : toSourceNameResolved;
}