naming conventions internals and lib api

[nicktaras]

###This is a location for an open discussion around the naming conventions used inside the source code and the API itself.

Initial naming conventions used with some suggestions:

The tokenLookupStore refers to an object that stores collection data.

Current: tokenLookupStore Suggestion: collectionLookupStore

The API and internals within the Token Negotiator use the term issuers to refer to the collections of NFTs or Off Chain Tokens.

Current: issuer(s) Suggestion: collection(s)

[nicktaras]

@micwallace - Adding you here as a location to review the naming conventions used inside the Token Negotiator as a general on going task as we optimise the code base.