Bytecode annotations - annotations op and custom backtraces

[François Perrad]

> OK, some people said yes and nobody screamed no, so these features are
> now in place, and backtrace is documented in the Exceptions PDD.
> Feedback and bug reports welcome.
>
The 2 methods 'backtrace' & 'annotations' in PMC Exception are useful
for post-mortem debug.
I think that PMC ParrotInterpreter needs the same methods with the
same interface ie the same output structure.
Many languages have a backtrace in their debug support.

The introspection interface of ParrotInterpreter needs to know annotations
   $P0 = getinterp
   $P1 = $P0['sub'; level]
   $P2 = $P0['annotations', level]  # currently not supported

François.

>
> Jonathan
>