Logging stacktraces on crashes and errors

[MaanooAk]

Is this left in deliberately?

freeage/third_party/loguru/loguru.cpp

Lines 594 to 596 in 1c6e375

	// install_signal_handlers(); // NOTE: CUSTOM CHANGE FOR LIBVIS (commented out)

Also this if condition could be changed in order to print the stack trace also in error level logs:

freeage/third_party/loguru/loguru.cpp

Lines 1207 to 1208 in 4789ae6

	if (message.verbosity == Verbosity_FATAL) {
	auto st = loguru::stacktrace(stack_trace_skip + 2);

In both cases it would be useful in bug reports to also have the stack trace without any additional actions.

Discovered while debugging...

[puzzlepaint]

I don't remember why I commented out install_signal_handlers();. If there's no problem with re-enabling it, I am fine with it. I remember getting some weird signals while debugging other projects that caused gdb to stop, maybe this was related to it; just a guess though.

Printing the stack trace on errors seems potentially useful, I agree.