Improve logging for ffi

[thesimplekid]

Currently all logging is lost with ffi, this can make debugging difficult. I Ideally we would have a way to pass the rust log up to the native logging interface. However, I am not sure this is possible. Another, solution would be to implement the file logging that we use in the mint and we should be able to access and review this file at least in a debug context.

[asmogo]

We could use println for this. We might want to check if we have FFI feature enabled and use a macro to determine if the logger should use tracing or println.