Atbash.py: Both raw_input() and unichr() were removed in Python 3 (#855)
Atbash.py: Both raw_input() and unichr() were removed in Python 3 (#855)

* Atbash.py: Both raw_input() and unichr() were removed in Python 3

@sateslayer and @AnupKumarPanwar your reviews please.

* Remove any leading / trailing whitespace from user input

TheAlgorithms/Python