Fix regressions in support for bytes / unicode

Fix regressions in support for bytes / unicode in certain APIs #15.
Added a check for _text_type, raise a DeprecationWarning and encode the
str to utf-8. This should preserve 0.13 API calls.
I used the 0.13 test suite with the 0.14 code and made the necessary
changes to make 0.13 and 0.14 tests pass.
2 files changed