print call trace on the panic handler

[sha0coder]

When there is a panic!() or any error is handled:

=== EMULATOR STATE AT PANIC === ...

But this hides the RUST_BACKTRACE it would be awesome to print a kind of backtrace or dont hide the backtrace.

I also replaced the .unwrap with a match that I put to get the instruction info. In the error handler unwrap and except are not convenient.