App manager.

This is a level of indirection over runwsgi, decoupling
test cases from runwsgi module.

Without an explicit dependency, tests can run against an
externally launched application, for example when
the python being tested cannot run the apps for various
reasons (e.g. threadless or too old).
Change test cases to use app manager
Standalone app runner
Option to not run in process test apps
Set up the app for certinfo test as well
Merge pull request #23 from p-push/external-apps

Using external applications in tests