Refactored checked_convert_to_int to use number_as_integer.
Made datum serialization format use datum_serialized_type_t instead of datum_t::type_t.
Merge branch 'sam_1427' into sam_1426
Made datum serialization use varint serialization for numeric datums that are integral.
Merge branch 'next' into sam_1426
Removed unused number_as_integer declaration in datum.hpp.
Merge branch 'sam_1426' into next