Hmm, some more things to try:
Make sure you've really (really) shut down the process. Try requesting the page after you've exited your program; your client (browser) should get a "connection refused."
Delete all
.pyc
files. (In particular, you should delete your own--bottle.pyc
isn't the problem.)Test your web service with curl or wget, not with a browser. This way you can absolutely eliminate the browser cache as a culprit.
That's it for off-the-top-of-my-head. If I think of more, I'll come back and add to the list. Good luck!