basic flexisettings settings proxy

this can be called through DJANGO_SETTINGS_MODULE without breaking django
import wrapped settings

* import settings through the proxy
* create a dictionary to cache import results
* add attribute access through __getattribute__()
* rename proxy class to FlexiSettingsProxy
add pip requirements file
basic unit testing
rename tests.base to tests.imports
add more imports tests

added test suite to make sure tests run in a certain order. Playing with
imports without unloading is messy and unloading modules is always a complex
task.
add comments about namespace pollution in tests
move common setUp() and tearDown() to base class
move from unittest to unittest2

this will provide things like setUpClass and tearDownClass
add setUpClass and tearDownClass in tests.base
create tests for settings lookup