allow to split and reuse aspect accross projects mixing inheritance and aspects

[dvojtise]

In the original cellular_automata sample, the rules have been splitted in several ecore files, one ecore is the core containing reusable part of the rule language, and the other ecore act as specialisation, one building an evolution language, one building an initialization language.

The original design specify the behavior of the reusable core in a project (using aspect), and each concrete language behavior is defined in a separate project.

(see figure in attachement for the global design)

Currently, the k3+xtend cannot deal with this and the concrete behavior (op2) isn't correctly called by the code in ReusableOp1 and still try to call the operation from the "abstract" B instead of the operation refined on B1