SetTimer doesn't work with 0 value

[cloudhead]

When setting a timer via Action::SetTimer, if a value of 0 is used, the timer never seems to expire.

[dr-orlovsky]

The question is what the timer should do in this case...

I mean 0 means "zero nanosecs", meaning that when it reaches reactor it is already a point in the past. But I understand that from an UI perspective this is counter-intuitive and it must do ... what?

[cloudhead]

It must be treated like any other duration: if the timer expired, trigger it as soon as possible.

[cloudhead]

Closed in #26