swift234

[demo] Tweak Obj-C version of uniq.
 - Use non-deprecated initWithContentsOfFile.
 - Avoid initWithFormat which is more "fair" to Obj-C in that the code is
   simpler (and much faster). Less fair in the sense that the Swift/Python
   versions using printf are more general.
 - Also, add a Python version just for comparison.

You should be saddened to learn the Python version is about 50% faster than the
Obj-C one even after the initWithFormat change.

Swift SVN r2486