Decouple fakes from test suite.

I've moved the python-logo.png next to the fakes function that should
return it unconditionally.  This way if someone is using the fakes
module outside of the test suite or in an installed version of pyrax (no
test suite), it will not cause problems trying to locate a missing
image.

I've also updated the MANIFEST.in and setup.py to reflect this change in
artifact location so it should continue getting pulled into the sdist
correctly.