* Delete sample folders of discontinued clients
* Remove duplicate python-flask server sample
The python-flask sample actually lives in samples/server/petstore/python-flask.
* Move hand-written test to "tests" folder
Now, "test" only contains generated stubs and all hand-written tests are in "tests".
* Delete left-over files in Python samples
These are not created by the generators (anymore) and not hand-written
for testing.
* Regenerate test file to fix import error