User-accessible objects should print nicely

[jpsamaroo]

As pointed out in #68 (comment), objects like RuntimeEvent{HSAStatusSignal} print as some monstrosity that can easily be mistaken for an error. We should make sure that all user-facing objects print decently.

[pxl-th]

Closing this as we now print most of the objects "nicely".
If there's need for more, please re-open.