Removed the int64_t datum_t constructor.
Merge branch 'sam_ql_refactor' into sam_ql_refactor_datum_constructor
Made us not use crazy enum scheme for serializer_wire_func_t subclasses.
Added comment about serializable_wire_func_t constructor rvalue references.
Removed serializable_wire_func_t, made map, filter, reduce, concatmap just inherit from wire_func_t.
Removed pb_rcheckable_t rebase method.
Made map_wire_func_t, etc, not inherit from pb_rcheckable_t.
Just made map_wire_func_t, etc, inherit publicly from wire_func_t.
Merge branch 'sam_ql_refactor_datum_constructor' into sam_ql_refactor
Merge branch 'sam_ql_refactor_func_private_inheritance' into sam_ql_refactor