REF: dispatch TDBlock.to_native_types to TDA._format_native_types
If we don't want to change the DataFrame/to_csv behavior, we could add the "0 days" back in to the TDI/TDA behavior.  That only requires changing 2 tests (both of which are directly testing Timedelta64Formatter) i think that would be better to add back to TDIFormatter updated nice!