fix aircraft undefined at sim startup

[smitty97]

if the program is running while the sim is starting up, simconnect connects but there is no initial aircraft, and the program would quit.

[maartentamboer]

Are these changes for FS2024?

[smitty97]

Not specifically for 2024, but works on either. Check the diff, it's a one-line bug fix, the variable aircraft is null when simconnect starts on sim launch, which causes an exception, so i just set it to "" at its declaration. It's been annoying me for a while in 2020 so I thought i'd try to fix it
the time bits are just for printing sim startup time info