* Extend the test of MonsterExtra
- Extend C++ test of MonsterExtra
- Add conversion of fbs/json NaNs to unsigned quiet-NaN
- Update documentation (cross-platform interoperability)
* Fix declaration of infinity constants int the test
* Add `NaN` and `Inf` defaults to the C++ generated code.
* Refactoring: add FloatConstantGenerator
* Refactoring-2:
- remove isnan checking for all float/double values
- add most probable implementation of virtual methods of FloatConstantGenerator
* Add conditional (FLATBUFFERS_NAN_DEFAULTS) isnan checking