raise URLError when CachedWeb gets non-200 code

This is to stop bad responses from being put into the python cache.
Merge pull request #22 from jeffjenkins/py-cache-error

raise URLError when CachedWeb gets non-200 code
Add .war extension to _map_jar

- this allows 3rdparty .war dependencies to be bundled into
  an app bundle.  You can use this to serve 3rdparty
  web applications from a jetty container server, and
  have this managed via ivy.
Merge pull request #23 from slackhappy/fs-nonbeta-warsupport

Add .war extension to _map_jar