Cleanup minor client debris
Refine base and client test cases
Make api version in client configurable

Default (current) is `v1`. Test included.
Add Foundation extension methods for query string deserialization
Add auth constants for redirect payload keys
Add initial auth example using custom url scheme

Note the naming convention of the scheme
(protocol) and the identifier. Also note the use of
provided constants and helpers.
Merge pull request #12 from 3dna/peng/minor-additions-1

Minor Additions #1

Minor additions to the client and sample app to
fill in some small gaps. Includes tests where
needed.