EntryIterator and EntryChangeIterator are arguably redundant

Fixed bug TagValueConversions.toBoolean
Could cause LegacyTagMap.EntryReader to produce incorrect answers to some queries

For simplicity, now treating Byte and Short as Integer.  That will make calling code doing primitive handling simpler.

Fleshing out tests -- more tests to come

Coverage for byte, short, float, and double

Updating the serializer to use TagMap traversal APIs.

By using new API, the serializer is now able to avoid boxing primitives when using OptimizedTagMap.