Implement default NYI stubs
I was finding it difficult to get started with a new schema or to add types to an existing schema since all of the pure virtual methods would need to be defined on the subclass before it could even link. The new feature in this release is that schemagen
will generate stub implementations which throw a std::runtime_error
exception and bubble up a "not implemented" message to the field error if they are not overridden.
This release also includes the fix for Issue #44 handling schema extensions and PR #42 which cleans up some of the USE_RAPIDJSON
handling in CMake.