File format for Compositional Grammar expressions needs review

[danka74]

Currently, the file format for CG expressions is very simple and was based on the previous version of CG (before 2014). Requirements differ and there seem to be (at least) two case:

1. having the definiens and the definiendum in the file as in the new CG language: (1234|definiens|)===(3456|definiendum|)
2. having only the definiendum in the file (possibly with a label) as in the existing format. URIs for new classes will have to be generated (possibly with namespace provided, UUIDs, numbers??)

Case 1 is fairly clear, but case 2 would need further elaboration, e.g. if it is needed at all.