Errors during webserver's startup scrambles the console when running in foreground

[schakko]

When the webserver crashes during startup (e.g. b/c of a configured but missing certificate file), the whole console output is scrambled if -background is not used.

Using defer termbox.Close() clears the whole screen. There is currently no other solution available, see nsf/termbox-go#233.
Not using defer termbox.Close() misses the console's reset operation.