Added approximate implementation of json I/O functionality for primitive types.
Added approximate implementation of json I/O functionality for complex types.
Added unit tests for JSON serialization of primitive and complex types, attendant bug fixes for issues encountered during testing.
Updated the README to remove descriptions of limitations that no longer apply (JSON serialization).  Added more examples to the README.  Updated the current version information in anticipation of the forthcoming 0.6.0 release.
Bumped version to 0.6.0 for release.