BugFix: Logging would divide by 0 if calculating standard deviation…

[Robadob]

…of variable for empty agent population.

Noticed it whilst investigating adding standard deviation to HostAPI.

[ptheywood]

Does this want to be static_cast<T>(0)? though it probably doesn't matter because casting 0 between any numeric type should be fine.

[Robadob]

Function returns type util::Any, I just copied the normal return statement rather than looking to deeply into it.

Logging has to store values of a bunch of types inside a map, hence the use of Any. The only possible problem i forsee here would be the Any storing 0 as type int, but it being read back as type double.

[Robadob]

Small change, tweaked it to util::Any(0.0), so its a double inside an Any.