FIBOFTF2 — Diffing surfaced that there is not agreement on Make Contract a subclass of Agreement

Contract is a subclass of Agreement
A contract is expressed via a communication (verbal or written)

Changes in Agreements and Contracts ontology; addition of Documents ontology and consequent change in People

Overview
This Issue Resolution addresses issue #16. This Issue Resolution also describes changes in response to the merge issue 14 (addition of UnilateralContract).

There are two components to the proposed changes for issue 16:

1. Make Contract a sub-class of Agreement (changing its semantics accordingly);

2. Introduce concepts for the physical expression of Written Contract, drawing upon new document concepts (contract document); also firm up the semantics of transferable contract by relating it to a new type of commitment in the Agreements ontology for commitments at large. There are additional changes in Agreements to firm up the nature of mutual or bilateral contracts, add the commitment at large concept. The concept of a unilateral commitment is already there and did not need to be added.
In addition

3. The addition of a Documents ontology, and consequent changes to the People ontology.

Then for Issue #14
4. Add Unilateral Contract to Contracts ontology.