Added DOxygen-style doctrings to most functions and methods #744

Job	Run time
windows-msvc-shared (CAPNPROTO)	6m 15s
windows-msvc-shared (PARQUET)	38m 50s
windows-msvc-shared (CBOR)	8m 44s
windows-msvc-shared (FLEXBUFFERS)	5m 8s
windows-msvc-shared (BOOST_SERIALIZATION)	5m 38s
windows-msvc-shared (JSON)	11m 16s
windows-msvc-shared (AVRO)	6m 57s
windows-msvc-shared (TOML)	3m 45s
windows-msvc-shared (YAML)	4m 33s
windows-msvc-shared (XML)	4m 1s
windows-msvc-shared (MSGPACK)	3m 34s
windows-msvc-shared (UBJSON)	7m 12s
windows-msvc (BOOST_SERIALIZATION)	6m 5s
windows-msvc (MSGPACK)	3m 47s
windows-msvc (CEREAL)	3m 59s
windows-msvc (CBOR)	9m 26s
windows-msvc (XML)	5m 16s
windows-msvc (JSON)	12m 35s
windows-msvc (UBJSON)	7m 23s
windows-msvc (FLEXBUFFERS)	6m 7s
windows-msvc (PARQUET)	37m 11s
windows-msvc (CAPNPROTO)	7m 56s
windows-msvc (TOML)	4m 27s
windows-msvc (benchmarks)	49m 41s
windows-msvc (YAML)	3m 58s
windows-msvc (AVRO)	7m 58s
	4h 31m 42s

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