Python 2.7 is pretty lenient about mixing and matching string types, but

Python 3.x is not. We had a number of places where we were comparing the

wrong types, or building strings with mixes of byte strings and Unicode

strings, or wrapping strings in bytes() instead of explicitly encoding

them.
This change fixes up all instances of bad string types, ensuring that

tests will pass on Python 3.x (when combined with upcoming changes

needed for hosting service compatibility).

Unit tests pass on Python 2.7 (and on 3.x with upcoming changes).