Apart from porting, only code logics change is the whole
encode()/decode() code because it created a string vs bytes mess and the
zipfile API apparently didn't like to deal with bytes, even though the
docs say otherwise.
It's hard to test on my UTF-8 system, so please anyone working with
non-UTF-8 paths, we welcome reports if ORA load/save does not work
properly.
Other than this, load, save and load_thumb were all tested and working
properly so far.