Cereal-ize

by Alexkar598
BYOND JSON (de)serialization with versioning and type checking
ID:2706527
 
This update doesnt bring much. The bump to 1.x.x is simply because I don't plan on changing the API in any major way in the future.

Changelog:
- Removed the JSON_ASSOC_SCAN_MODE define as it was clunky to use and didn't serve much purpose.
- Renamed JSON_migrable_versions to JSON_migratable_versions