Hey @bilderbuchi - it is a good question re: non-throw exceptions.

Looking @ the code, it seems unlikely, but the point of this is a last line of defense against uncaught exceptions, so I'd propose that we just use `cerr` as our output stream.

We just need to make a note of this in our docs, so people making sub-classes don't inadvertently do it.

@ofTheo If we go with `cerr`, this could possible all go back in `ofTypes.h` since it wont' create the circ dependency issue I mentioned on IRC.