Evaluate required functions

[graybeal]

Review user scenarios at https://docs.google.com/document/d/1DxU2IN56fUoASxaiEOsn2NDtjRGWw5rK_BxRAKcyvwU/edit, evaluate for applicability to current hackathon. Consider how to address in UI (#9).

[graybeal]

I created the pull requests #11 and #12 to include my breakdown of the functions that are required for your use cases. We'll mostly get to the first category of functions in that list:
*** Understanding Prefixes
prefix available or taken
most credible target for prefix
in which registry/ies
Documentation: For given registry's entry for this prefix:

• Primary prefix
• Alternate prefix
• Entity identifier (e.g., IRI)
• Identifier namespace path if different (e.g., includes # or / separator)
  • identifier resolution - computable (y/n)
  • identifier resolution - human viewable (y/n)
• different namespace for human readable pages
• homepage
• description
• title
• more detailed metadata about the entry
  • Local identifier (e.g., DB record key)
  • who registered
  • when registered

Then the second category we might be able to show, if we can come up with some decent tests.

*** Understanding Prefixes: Errors
prefix clashes - one prefix, multiple resources
prefix ambiguity - one prefix, maybe multiple resources
redundant primary prefixes per resource - more than one prefix

I may add some analysis of how we might present this info most cleanly, per #9.