Handle operation with depth > 1

[stombre]

Introduction

Currently the ORM support direct link
A ref B
A.linkedWith B !!

This issue is an idea to introduce more depth;
A ref B
B ref C
A linkedWith C

Todo

• Resolve deep relation between concept (in Relation class ? Dummy vs A* / Djistra ?)
• Make linkedWith work with deep reference
• Way to overload behavior when resolving complex reference (for handling join operator in SQL eventually)