Adds __version__
Fixes unicode/bytes issues for Python 3
More unicode fixes

Don't use % with bytes, Python 3 won't have it.

Make sure to convert paths to bytes before _chdir().

Don't use raw bytes from the server as exception message.

Handling paths on Windows is annoying: local part is assumed to be in
local encoding (cp1252 on my machine), remote part is assumed to be
UTF-8.
Fixes spaces in filenames
Adds tests
Fixes _chdir() on PY3
Fixes _chdir() on Windows
Fixes tests on OS X

OS X has yet a different approach to filenames. This is insane.
Fixes test on Python 3 on OS X
Merge pull request #39 from remram44/python3

Python3 & unicode