Avoid "Swiss Army Knife" syndrome!
Verbs here:

• update verbNoun Dictionary wiki: https://github.com/JuliaRobotics/DistributedFactorGraphs.jl/wiki/Standard-Definitions-of-API-via-verbs-and-set-theory

With regard to:

• Signature
• Return Type
• Error Behaviour

Core verbs:

• list
• get
• add
• delete
• merge
• has[Noun]
• is[Adjective]

Other

• sync
• save
• load
• copyto
• search

TODO add all verbs for DFG v1.0

Considered but not in the API: , update, set, pull/push (use Async modifier)