Fixes #133, creates API for Maps and Lists for consistent data checking

[imjoshdean]

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For #133:

If can/map is being used alongside fall-through-cache, new attributes will be added to Maps and Lists.

• isConsistent() will return true if the data is actively in sync with the data from the server, false if it's relying on fall-back-cache's cached data.
• inconsistencyReason will return the base connection's rejected promise error, should there be one.

[justinbmeyer]

Thanks @imjoshdean. Please let me know if you have any thoughts about this stuff.

[imjoshdean]

Thoughts provided inline!

[matthewp]

@justinbmeyer this is waiting review.