Proposal: weakly deprecate IAO and OIO term_editor and oio:created_by

[cmungall]

original issue: #60

Here, weakly deprecate means we put a comment on these two properties saying their usage is no longer favored, and new terms should use other properties, either dcterms creator or contributor

This issue is not for discussing which of dcterms creator or contributor to use - see #120 for that.

[matentzn]

Fully supportive of that - but I am not sure if we have to reach agreement on wether ontologies should be internally using term editor or not - the question should be if we can ignore these properties for attribution quantification. But in any case - I still support the motion, I just doubt @zhengj2007 and the OBI world will see the need for retiring IAO:term editor (churn argument). But maybe I will be surprised!