[Exception] Now includes null checks before printing stack_trace object
[Exception] Now includes null checks before printing stack_trace object

- Allows extended Exceptions to set stack_trace = null to avoid overhead.
- For when e.g. exceptions are used for asynch control rather than errors.

AbePralle/Rogue,AbePralle/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue,Plasmaworks/Rogue