Importjson

Solved Outstanding major Issue 18
Ensured that package is Py27 and Py35 compliant.

Issue 8 : fixed - Inheritance of default attribute values.

Issue 6 : Implemented ability to constrain type of Instance Attribute to be one of the classes in the module.
Issue 4 : Implemented "read_only"
Issue 5 : Implemented "not_none"
Corrected Readme so that table render correctly on github & pyPI (github pages still an issue).
Added more unit tests : now at 99% coverage (1 line unreached - 159 total)

Corrected some errors in the Readme - no functional change

Automatically differentiate between the two forms of json file. Make AllDictionariesAreClasses config item obsolete.

Update README with more details of constraints. Fixed bugs in the import.  Refactored generated constrains code to allow easy subclass (to add extra constrains. Refactored some tests to remove repetition of tests case while still getting the same coverage.  Added Examples directory.