Changes:
* replace `iotuil` elements with the ones from `os` package;
* replace `os.Filemode` with `fs.FileMode`;
* use `signal.NotifyContext` instead of `NewGracefulContext` (removed).
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Scanning csv-table entries one-by-one takes significant time and system
resources. To speed up random access to table records, on the first call,
the table is pumped into memory (map). On subsequent calls, I/O operations
are not performed.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
Implement airport database based on csv OpenFlights table. Implement
UN/LOCODE entry matcher. Implement country namespace.
Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
