Implement time zone support for firebird 4.

[andy-123]

Add time zone support for firebird 4

Add a new option to "Data Grid"-preferences to select how time zones are displayed: none, id or name.

To display the names of the time zones the table RDB$TIME_ZONES is loaded. This is done when opening a database (ODS version >= 13.0).

[arvanus]

Nice! Do you plan to add support for int128 too? Thanks

[andy-123]

Do you plan to add support for int128 too?

Yes. After this is merged.

[arvanus]

Done :)

[arvanus]

Found 2 problems with timestamp and time:

select cast (current_timestamp as TIMESTAMP without time zone) as ok, current_timestamp as also_ok, cast (current_timestamp as TIMESTAMP without time zone) as buggy_zero_day from rdb$database

Just in the thirty column, the date is 31.12.1899 and the time is correct

select cast (current_time as TIME without time zone) as no_ms_value, current_time as no_ms_value, cast (current_time as TIME without time zone) as has_ms_but_dif_sec from rdb$database

in this SQL, the MS part is always zeroed, but in the thirty column there is a MS value, and the sec is different

[andy-123]

Thank you for reporting. I will have a look at it.