how to disable exception catching entirely

[theo-walton]

Hey, the codebase I work on has very nice C++ stack traces that happen when code aborts or exceptions are uncaught. However when we make pybinds of this C++ code, all uncaught exceptions are caught and re-thrown as python exceptions which looses information about the stack traces.

Since we never use exceptions in our C++ code an option to disable automatic exception catching in pybinds would be very useful as we have a few cases where 3rd party libraries will throw exceptions that are getting hidden by pybinds exception handling