Include stacktrace in log for `rescue_crashes`

[ghivert]

Hi!

When doing some FFI crimes, Erlang throws an error. When an error is thrown, in case wisp.rescue_crashes is used, Wisp will take care of the error, but will discard the error in the display. It would be nice to preserve the stacktrace during display.

[lpil]

Thanks! The issue is not that is discards the error, it's that it doesn't include the stack trace when logging.