Allows arbitrary combinations of Python imports to be aggregated into a single
application. This application is defined using an application configuration file
("appconf") similar to Django's urlconf:

>>> from appspace import patterns
>>> apps = patterns(
...    'helpers',
...    ('square', 'math.sqrt'),
...    ('fabulous', 'math.fabs'),
...    include('subapp', 'foo.bar')
... )

Members of an application objects can be accessed as object attributes,
dictionary keys, or through the application object's __call__ interface:

>>> fab1 = plug.helpers.fabulous
>>> fab2 = plug['helpers']['fabulous']
>>> fab1(2)
2.0
>>> fab2(2)
2.0
>>> plug.helpers.fabulous(2)
2.0
>>> plug('fabulous', 2)
2.0