Check if times are handled properly

[István Váradi]

• Whether the timestamp returned by the simulator contains the date, and if not, take care of wrapping over at midnight (during difference calculations in checks and in case of block and flight times) -> the best would be to handle it in the FSUIPC layer
• In the booked flight: if the arrival time is less than the departure time, 1 day should be added to the former

[István Váradi]

• The timestamps did include the full date, so everything else that depends on it should work well.
• Fixed the way it is handled for the booked flights.