Fixes Issue #57

[someone1]

Moves pipeline from /_ah/pipeline/ to /_pipeline/.
Also fixes up demo code

[soundofjw]

lgtm, just not sure about the architecture decision, reserving that for the googlers.

fwiw: there is nothing in here to ease the transition of queued tasks that are presently pointing to the _ah prefix.

[someone1]

if you keep both entries in your YAML file it should go through fine. both new and old will end up executing on the correct routes, just new pipes will use the new route.

You can also specify the base URL when starting each pipeline, so that way you can explicitly keep all your current pipelines on the old path, and slowly remove the explicit arg for the ones that are not executing when deployed.

[mikelambert]

@tkaitchuck , any thoughts here? I'm not sure about the best choice of prefix, but I do agree something like this should be committed to ensure this code works on AppEngine Managed VMs (which is the future of AppEngine, from what I hear). Thanks.