* consistency of output in python 2
print("string") and print "string" have the same behavior in Python 2 and 3, but print("string", "string") will print a tuple in Python 2
* Add requirement
Update readme to include info on the one required library, requests, including a pip install command.
Always return a pair from the lookup_pwned_api so that destructuring
assignment can be safely used when calling the function. The second
argument being zero indicates the password has not been found in the
pwend database.
While at it, document the function.
