* Remove the dependency on PredefinedLocalMessage from generic fit parsing code
* Standardize toString methods, omit types for known fields
* Return null on unknown field number or names, instead of crashing
* Map more Global FIT messages (device info, monitoring, sleep stages, sleep stats, stress level)
* Prioritize "timestamp" over "253_timestamp" if specified explicitly in the global message definition
* Introduce RecordData wrappers for each global message, allowing us to have proper types when getting data. If missing or unknown, the getter returns null. All classes are auto-generated by the FitCodeGen.
* Persist a list of RecordData, instead of a Map from RecordDefinition
* Fix parsing of compressed timestamps - keep them in computedTimestamp on each data record
* Use timestamp16 if available in Monitoring records
